fix: Issues With Behaviours Entering / Leaving the Hierarchy Callbacks Not Firing

- TryGetBehaviourInParent
- GetBehaviourInParent
- TryGetBehaviourInChildren
- GetBehaviourInChildren

Engine.Core/Abstract/Assignable/IAssignable.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IAssignable
     /// <summary>
     /// Event triggered when the <see cref="IAssignable"/>'s fields are unassigned and completely ready to recycle.
     /// </summary> 
-    Action<IAssignable>? OnUnassigned { get; set; }
+    event OnUnassignedDelegate? OnUnassigned;
 
     /// <summary>
     /// Unassign <see cref="IAssignable"/>'s all fields and make it ready to recycle.
@@ -19,4 +17,6 @@ public interface IAssignable
     /// <see cref="true"/>, if the fields are unsigned successfully, <see cref="false"/> if not.
     /// </returns>
     bool Unassign();
+
+    delegate void OnUnassignedDelegate(IAssignable sender);
 }

Engine.Core/Abstract/Assignable/IAssignableBehaviourController.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IAssignableBehaviourController : IAssignable
     /// <summary>
     /// Event triggered when the <see cref="IBehaviourController"/> value has has been assigned a new value.
     /// </summary>
-    Action<IAssignableBehaviourController>? OnBehaviourControllerAssigned { get; set; }
+    event OnBehaviourControllerAssignedDelegate? OnBehaviourControllerAssigned;
 
     /// <inheritdoc cref="IBehaviourController" />
     IBehaviourController BehaviourController { get; }
@@ -23,4 +21,6 @@ public interface IAssignableBehaviourController : IAssignable
     /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
     /// </returns>
     bool Assign(IBehaviourController behaviourController);
+
+    delegate void OnBehaviourControllerAssignedDelegate(IAssignableBehaviourController sender);
 }

Engine.Core/Abstract/Assignable/IAssignableEntity.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IAssignableEntity : IAssignable
     /// <summary>
     /// Event triggered when the <see cref="IEntity"/> value has has been assigned a new value.
     /// </summary>
-    Action<IAssignableEntity>? OnEntityAssigned { get; set; }
+    event OnEntityAssignedDelegate? OnEntityAssigned;
 
     /// <inheritdoc cref="IEntity" />
     IEntity Entity { get; }
@@ -23,4 +21,6 @@ public interface IAssignableEntity : IAssignable
     /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
     /// </returns>
     bool Assign(IEntity entity);
+
+    delegate void OnEntityAssignedDelegate(IAssignableEntity sender);
 }

Engine.Core/Abstract/Assignable/IAssignableGameManager.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IAssignableGameManager : IAssignable
     /// <summary>
     /// Event triggered when the <see cref="IGameManager"/> value has has been assigned a new value.
     /// </summary>
-    Action<IAssignableGameManager>? OnGameManagerAssigned { get; set; }
+    event OnGameManagerAssignedDelegate? OnGameManagerAssigned;
 
     /// <inheritdoc cref="IGameManager" />
     IGameManager GameManager { get; }
@@ -23,4 +21,6 @@ public interface IAssignableGameManager : IAssignable
     /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
     /// </returns>
     bool Assign(IGameManager gameManager);
+
+    delegate void OnGameManagerAssignedDelegate(IAssignableGameManager sender);
 }

Engine.Core/Abstract/Assignable/IAssignableGameObject.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IAssignableGameObject : IAssignable
     /// <summary>
     /// Event triggered when the <see cref="IGameObject"/> value has has been assigned a new value.
     /// </summary>
-    Action<IAssignableGameObject>? OnGameObjectAssigned { get; set; }
+    event OnGameObjectAssignedDelegate? OnGameObjectAssigned;
 
     /// <inheritdoc cref="IGameObject" />
     IGameObject GameObject { get; }
@@ -23,4 +21,6 @@ public interface IAssignableGameObject : IAssignable
     /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
     /// </returns>
     bool Assign(IGameObject gameObject);
+
+    delegate void OnGameObjectAssignedDelegate(IAssignableGameObject sender);
 }

Engine.Core/Abstract/Assignable/IAssignableStateEnable.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IAssignableStateEnable : IAssignable
     /// <summary>
     /// Event triggered when the <see cref="IStateEnable"/> value has has been assigned a new value.
     /// </summary>
-    Action<IAssignableStateEnable>? OnStateEnableAssigned { get; set; }
+    event OnStateEnableAssignedDelegate? OnStateEnableAssigned;
 
     /// <inheritdoc cref="IStateEnable" />
     IStateEnable StateEnable { get; }
@@ -23,4 +21,6 @@ public interface IAssignableStateEnable : IAssignable
     /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
     /// </returns>
     bool Assign(IStateEnable stateEnable);
+
+    delegate void OnStateEnableAssignedDelegate(IAssignableStateEnable sender);
 }

Engine.Core/Abstract/Assignable/IAssignableTransform.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IAssignableTransform : IAssignable
     /// <summary>
     /// Event triggered when the <see cref="ITransform"/> value has has been assigned a new value.
     /// </summary>
-    Action<IAssignableTransform>? OnTransformAssigned { get; set; }
+    event OnTransformAssignedDelegate? OnTransformAssigned;
 
     /// <inheritdoc cref="ITransform" />
     ITransform Transform { get; }
@@ -23,4 +21,6 @@ public interface IAssignableTransform : IAssignable
     /// <see cref="true"/>, if the value given assigned successfully assigned, <see cref="false"/> if not.
     /// </returns>
     bool Assign(ITransform transform);
+
+    delegate void OnTransformAssignedDelegate(IAssignableTransform sender);
 }

Engine.Core/Abstract/Assignable/IHierarchyObject.cs

@@ -0,0 +1,64 @@
+namespace Syntriax.Engine.Core.Abstract;
+
+/// <summary>
+/// Represents an <see cref="IEntity"/> that can enter and exit a hierarchy within the <see cref="IGameManager"/> system.
+/// This interface allows for tracking the object's presence in the hierarchy and provides events 
+/// for notifying when the see enters or exits the hierarchy.
+/// </summary>
+public interface IHierarchyObject : IEntity, INameable
+{
+    /// <summary>
+    /// Event triggered when the <see cref="IEntity"/> enters the hierarchy.
+    /// </summary>
+    event OnEnteredHierarchyDelegate? OnEnteredHierarchy;
+
+    /// <summary>
+    /// Event triggered when the <see cref="IEntity"/> exits the hierarchy.
+    /// </summary>
+    event OnExitedHierarchyDelegate? OnExitedHierarchy;
+
+    /// <summary>
+    /// Gets the <see cref="IGameManager"/> associated with this <see cref="IEntity"/> , if any.
+    /// </summary>
+    IGameManager? GameManager { get; }
+
+    /// <summary>
+    /// Indicates whether the <see cref="IEntity"/> is currently in the hierarchy.
+    /// </summary>
+    bool IsInHierarchy { get; }
+
+    /// <summary>
+    /// Internal method to handle entering the hierarchy.
+    /// This should be called by the system to properly manage hierarchy states.
+    /// </summary>
+    /// <param name="gameManager">The game manager that is managing this hierarchy.</param>
+    /// <returns>
+    /// <see cref="true"/> if the <see cref="IEntity"/> successfully entered the hierarchy; 
+    /// <see cref="false"/> if it failed to do so.
+    /// </returns>
+    internal bool EnterHierarchy(IGameManager gameManager);
+
+    /// <summary>
+    /// Internal method to handle exiting the hierarchy.
+    /// This should be called by the system to properly manage hierarchy states.
+    /// </summary>
+    /// <returns>
+    /// <see cref="true"/> if the <see cref="IEntity"/> successfully exited the hierarchy; 
+    /// <see cref="false"/> if it failed to do so.
+    /// </returns>
+    internal bool ExitHierarchy();
+
+    /// <summary>
+    /// Delegate type for the event triggered when the <see cref="IEntity"/> enters the hierarchy of a <see cref="IGameManager">.
+    /// </summary>
+    /// <param name="sender">The <see cref="IEntity"/> that entered the hierarchy.</param>
+    /// <param name="gameManager">The <see cref="IGameManager"/> that the <see cref="IEntity"/> has entered it's hierarchy.</param>
+    delegate void OnEnteredHierarchyDelegate(IHierarchyObject sender, IGameManager gameManager);
+
+    /// <summary>
+    /// Delegate type for the event triggered when the <see cref="IEntity"/> exits the hierarchy of a <see cref="IGameManager">.
+    /// </summary>
+    /// <param name="sender">The <see cref="IEntity"/> that exited the hierarchy.</param>
+    /// <param name="gameManager">The <see cref="IGameManager"/> that the <see cref="IEntity"/> has exited it's hierarchy.</param>
+    delegate void OnExitedHierarchyDelegate(IHierarchyObject sender, IGameManager gameManager);
+}

Engine.Core/Abstract/BaseEntity.cs

@@ -1,16 +1,18 @@
 using System;
 
+using Syntriax.Engine.Core.Exceptions;
+
 namespace Syntriax.Engine.Core.Abstract;
 
 public abstract class BaseEntity : IEntity
 {
-    public Action<IEntity, string>? OnIdChanged { get; set; } = null;
+    public event IEntity.OnIdChangedDelegate? OnIdChanged = null;
 
-    public Action<IAssignable>? OnUnassigned { get; set; } = null;
+    public event IInitialize.OnInitializedDelegate? OnInitialized = null;
-    public Action<IAssignableStateEnable>? OnStateEnableAssigned { get; set; } = null;
+    public event IInitialize.OnFinalizedDelegate? OnFinalized = null;
 
-    public Action<IInitialize>? OnInitialized { get; set; } = null;
+    public event IAssignableStateEnable.OnStateEnableAssignedDelegate? OnStateEnableAssigned = null;
-    public Action<IInitialize>? OnFinalized { get; set; } = null;
+    public event IAssignable.OnUnassignedDelegate? OnUnassigned = null;
 
 
     private IStateEnable _stateEnable = null!;
@@ -37,7 +39,7 @@ public abstract class BaseEntity : IEntity
         }
     }
 
-    public bool Initialized
+    public bool IsInitialized
     {
         get => _initialized;
         private set
@@ -55,7 +57,7 @@ public abstract class BaseEntity : IEntity
 
     public bool Assign(IStateEnable stateEnable)
     {
-        if (Initialized)
+        if (IsInitialized)
             return false;
 
         _stateEnable = stateEnable;
@@ -67,11 +69,13 @@ public abstract class BaseEntity : IEntity
     protected virtual void UnassignInternal() { }
     public bool Unassign()
     {
-        if (Initialized)
+        if (IsInitialized)
             return false;
 
         UnassignInternal();
 
+        _stateEnable = null!;
+        _stateEnable.Unassign();
         OnUnassigned?.Invoke(this);
         return true;
     }
@@ -79,24 +83,26 @@ public abstract class BaseEntity : IEntity
     protected virtual void InitializeInternal() { }
     public bool Initialize()
     {
-        if (Initialized)
+        if (IsInitialized)
             return false;
 
+        NotAssignedException.Check(this, _stateEnable);
+
         InitializeInternal();
 
-        Initialized = true;
+        IsInitialized = true;
         return true;
     }
 
     protected virtual void FinalizeInternal() { }
     public bool Finalize()
     {
-        if (!Initialized)
+        if (!IsInitialized)
             return false;
 
         FinalizeInternal();
 
-        Initialized = false;
+        IsInitialized = false;
         return true;
     }
 

Engine.Core/Abstract/IBehaviour.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,7 +8,7 @@ public interface IBehaviour : IEntity, IAssignableBehaviourController, IAssignab
     /// <summary>
     /// Event triggered when the priority of the <see cref="IBehaviour"/> changes.
     /// </summary>
-    Action<IBehaviour>? OnPriorityChanged { get; set; }
+    event OnPriorityChangedDelegate? OnPriorityChanged;
 
     /// <summary>
     /// The priority of the <see cref="IBehaviour"/>.
@@ -21,4 +19,6 @@ public interface IBehaviour : IEntity, IAssignableBehaviourController, IAssignab
     /// The value indicating whether the <see cref="IBehaviour"/> is active.
     /// </summary>
     bool IsActive { get; }
+
+    delegate void OnPriorityChangedDelegate(IBehaviour sender, int previousPriority);
 }

Engine.Core/Abstract/IBehaviourController.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 
@@ -7,32 +6,32 @@ namespace Syntriax.Engine.Core.Abstract;
 /// <summary>
 /// Represents a controller for managing <see cref="IBehaviour"/>s and notify them accordingly about the engine's updates. Connected to an <see cref="IGameObject"/>.
 /// </summary>
-public interface IBehaviourController : IAssignableGameObject, IEnumerable<IBehaviour>
+public interface IBehaviourController : IInitialize, IAssignableGameObject, IEnumerable<IBehaviour>
 {
     /// <summary>
     /// Event triggered before the update of <see cref="IBehaviour"/>s.
     /// </summary>
-    Action<IBehaviourController>? OnPreUpdate { get; set; }
+    event OnPreUpdateDelegate? OnPreUpdate;
 
     /// <summary>
     /// Event triggered during the update of <see cref="IBehaviour"/>s.
     /// </summary>
-    Action<IBehaviourController>? OnUpdate { get; set; }
+    event OnUpdateDelegate? OnUpdate;
 
     /// <summary>
     /// Event triggered before the drawing phase.
     /// </summary>
-    Action<IBehaviourController>? OnPreDraw { get; set; }
+    event OnPreDrawDelegate? OnPreDraw;
 
     /// <summary>
     /// Event triggered when a <see cref="IBehaviour"/> is added to the <see cref="IBehaviourController"/>.
     /// </summary>
-    Action<IBehaviourController, IBehaviour>? OnBehaviourAdded { get; set; }
+    event OnBehaviourAddedDelegate? OnBehaviourAdded;
 
     /// <summary>
     /// Event triggered when a <see cref="IBehaviour"/> is removed from the <see cref="IBehaviourController"/>.
     /// </summary>
-    Action<IBehaviourController, IBehaviour>? OnBehaviourRemoved { get; set; }
+    event OnBehaviourRemovedDelegate? OnBehaviourRemoved;
 
     /// <summary>
     /// Adds a <see cref="IBehaviour"/> to the <see cref="IBehaviourController"/>.
@@ -102,4 +101,11 @@ public interface IBehaviourController : IAssignableGameObject, IEnumerable<IBeha
     /// Performs pre-draw operations.
     /// </summary>
     void UpdatePreDraw();
+
+    delegate void OnPreUpdateDelegate(IBehaviourController sender);
+    delegate void OnUpdateDelegate(IBehaviourController sender);
+    delegate void OnPreDrawDelegate(IBehaviourController sender);
+    delegate void OnBehaviourAddedDelegate(IBehaviourController sender, IBehaviour behaviourAdded);
+    delegate void OnBehaviourRemovedDelegate(IBehaviourController sender, IBehaviour behaviourRemoved);
+
 }

Engine.Core/Abstract/ICoroutineYield.cs

@@ -0,0 +1,8 @@
+using System.Collections;
+
+namespace Syntriax.Engine.Core.Abstract;
+
+public interface ICoroutineYield
+{
+    bool Yield();
+}

Engine.Core/Abstract/IEntity.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -11,10 +9,12 @@ public interface IEntity : IInitialize, IAssignableStateEnable
     /// Event triggered when the <see cref="Id"/> of the <see cref="IEntity"/> changes.
     /// The string action parameter is the previous <see cref="Id"/> of the <see cref="IEntity"/>. 
     /// </summary>
-    Action<IEntity, string>? OnIdChanged { get; set; }
+    event OnIdChangedDelegate? OnIdChanged;
 
     /// <summary>
     /// The ID of the <see cref="IEntity"/>.
     /// </summary>
     string Id { get; set; }
+
+    delegate void OnIdChangedDelegate(IEntity sender, string previousId);
 }

Engine.Core/Abstract/IGameManager.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Generic;
 
 namespace Syntriax.Engine.Core.Abstract;
@@ -8,15 +7,35 @@ namespace Syntriax.Engine.Core.Abstract;
 /// </summary>
 public interface IGameManager : IEntity, IEnumerable<IGameObject>
 {
+    /// <summary>
+    /// Event triggered when <see cref="Update(EngineTime)"/> is called on the <see cref="IGameManager"/>.
+    /// </summary>
+    event OnUpdateDelegate? OnUpdate;
+
+    /// <summary>
+    /// Event triggered when <see cref="PreDraw"/> is called on the <see cref="IGameManager"/>.
+    /// </summary>
+    event OnPreDawDelegate? OnPreDraw;
+
     /// <summary>
     /// Event triggered when a <see cref="IGameObject"/> is registered to the <see cref="IGameManager"/>.
     /// </summary>
-    Action<IGameManager, IGameObject>? OnGameObjectRegistered { get; set; }
+    event OnGameObjectRegisteredDelegate? OnGameObjectRegistered;
 
     /// <summary>
     /// Event triggered when a <see cref="IGameObject"/> is unregistered from the <see cref="IGameManager"/>.
     /// </summary>
-    Action<IGameManager, IGameObject>? OnGameObjectUnRegistered { get; set; }
+    event OnGameObjectUnRegisteredDelegate? OnGameObjectUnRegistered;
+
+    /// <summary>
+    /// Event triggered when a <see cref="IHierarchyObject"/> is registered to the <see cref="IGameManager"/>.
+    /// </summary>
+    event OnHierarchyObjectRegisteredDelegate? OnHierarchyObjectRegistered;
+
+    /// <summary>
+    /// Event triggered when a <see cref="IHierarchyObject"/> is unregistered from the <see cref="IGameManager"/>.
+    /// </summary>
+    event OnHierarchyObjectUnRegisteredDelegate? OnHierarchyObjectUnRegistered;
 
     /// <summary>
     /// Gets a read-only list of <see cref="IGameObject"/>s managed by the <see cref="IGameManager"/>.
@@ -24,10 +43,15 @@ public interface IGameManager : IEntity, IEnumerable<IGameObject>
     IReadOnlyList<IGameObject> GameObjects { get; }
 
     /// <summary>
-    /// Registers a <see cref="IGameObject"/> to the <see cref="IGameManager"/>.
+    /// Gets a read-only list of <see cref="IHierarchyObject"/>s managed by the <see cref="IGameManager"/>.
     /// </summary>
-    /// <param name="gameObject">The <see cref="IGameObject"/> to register.</param>
+    IReadOnlyList<IHierarchyObject> HierarchyObjects { get; }
-    void RegisterGameObject(IGameObject gameObject);
+
+    /// <summary>
+    /// Registers an <see cref="IHierarchyObject"/> to the <see cref="IGameManager"/>.
+    /// </summary>
+    /// <param name="hierarchyObject">The <see cref="IHierarchyObject"/> to register.</param>
+    void Register(IHierarchyObject hierarchyObject);
 
     /// <summary>
     /// Instantiates a <see cref="IGameObject"/> of type T with the given arguments and registers it to the <see cref="IGameManager"/>.
@@ -38,11 +62,10 @@ public interface IGameManager : IEntity, IEnumerable<IGameObject>
     T InstantiateGameObject<T>(params object?[]? args) where T : class, IGameObject;
 
     /// <summary>
-    /// Removes a <see cref="IGameObject"/> from the <see cref="IGameManager"/>.
+    /// Removes an <see cref="IHierarchyObject"/> from the <see cref="IGameManager"/>.
     /// </summary>
-    /// <param name="gameObject">The <see cref="IGameObject"/> to remove.</param>
+    /// <param name="hierarchyObject">The <see cref="IHierarchyObject"/> to remove.</param>
-    /// <returns>The removed <see cref="IGameObject"/>.</returns>
+    void Remove(IHierarchyObject hierarchyObject);
-    IGameObject RemoveGameObject(IGameObject gameObject);
 
     /// <summary>
     /// Updates the <see cref="IGameManager"/> with the given engine time data.
@@ -54,4 +77,12 @@ public interface IGameManager : IEntity, IEnumerable<IGameObject>
     /// Performs operations that should be done before the draw calls.
     /// </summary>
     void PreDraw();
+
+    delegate void OnUpdateDelegate(IGameManager sender, EngineTime time);
+    delegate void OnPreDawDelegate(IGameManager sender);
+
+    delegate void OnGameObjectRegisteredDelegate(IGameManager sender, IGameObject gameObjectRegistered);
+    delegate void OnGameObjectUnRegisteredDelegate(IGameManager sender, IGameObject gameObjectUnregistered);
+    delegate void OnHierarchyObjectRegisteredDelegate(IGameManager sender, IHierarchyObject hierarchyObjectRegistered);
+    delegate void OnHierarchyObjectUnRegisteredDelegate(IGameManager sender, IHierarchyObject hierarchyObjectUnregistered);
 }

Engine.Core/Abstract/IGameObject.cs

@@ -1,19 +1,19 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
 /// Represents a game object with various properties and functionalities.
 /// </summary>
-public interface IGameObject : IEntity, IAssignableGameManager, IAssignableTransform, IAssignableBehaviourController, INameable, IInitialize
+public interface IGameObject : IEntity, IHierarchyObject, IAssignableTransform, IAssignableBehaviourController, INameable, IInitialize
 {
     /// <summary>
     /// Event triggered when the <see cref="Update"/> method is called.
     /// </summary>
-    Action<IGameObject>? OnUpdated { get; set; }
+    event OnUpdatedDelegate? OnUpdated;
 
     /// <summary>
     /// Updates the game object.
     /// </summary>
     void Update();
+
+    delegate void OnUpdatedDelegate(IGameObject sender);
 }

Engine.Core/Abstract/IInitialize.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,17 +8,17 @@ public interface IInitialize
     /// <summary>
     /// Event triggered when the <see cref="Initialize"/> method is called successfully.
     /// </summary>
-    Action<IInitialize>? OnInitialized { get; set; }
+    event OnInitializedDelegate? OnInitialized;
 
     /// <summary>
     /// Event triggered when the <see cref="Finalize"/> method is called successfully.
     /// </summary>
-    Action<IInitialize>? OnFinalized { get; set; }
+    event OnFinalizedDelegate? OnFinalized;
 
     /// <summary>
     /// The value indicating whether the entity has been initialized.
     /// </summary>
-    bool Initialized { get; }
+    bool IsInitialized { get; }
 
     /// <summary>
     /// Initializes the entity.
@@ -33,4 +31,7 @@ public interface IInitialize
     /// </summary>
     /// <returns><see cref="true"/> if finalization is successful, otherwise <see cref="false"/>.</returns>
     bool Finalize();
+
+    delegate void OnInitializedDelegate(IInitialize sender);
+    delegate void OnFinalizedDelegate(IInitialize sender);
 }

Engine.Core/Abstract/INameable.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,10 +8,12 @@ public interface INameable
     /// <summary>
     /// Event triggered when the name of the entity changes.
     /// </summary>
-    Action<IEntity>? OnNameChanged { get; set; }
+    event OnNameChangedDelegate? OnNameChanged;
 
     /// <summary>
     /// The name of the entity.
     /// </summary>
     string Name { get; set; }
+
+    delegate void OnNameChangedDelegate(INameable sender, string previousName);
 }

Engine.Core/Abstract/IStateEnable.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
@@ -10,10 +8,12 @@ public interface IStateEnable : IAssignableEntity
     /// <summary>
     /// Event triggered when the <see cref="Enabled"/> state of the <see cref="IStateEnable"/> changes.
     /// </summary>
-    Action<IStateEnable>? OnEnabledChanged { get; set; }
+    event OnNameChangedDelegate? OnEnabledChanged;
 
     /// <summary>
     /// The value indicating whether the <see cref="IStateEnable"/> is enabled.
     /// </summary>
     bool Enabled { get; set; }
+
+    delegate void OnNameChangedDelegate(IStateEnable sender, bool previousState);
 }

Engine.Core/Abstract/ITransform.cs

@@ -1,39 +1,105 @@
 using System;
+using System.Collections.Generic;
 
 namespace Syntriax.Engine.Core.Abstract;
 
 /// <summary>
 /// Represents the transformation properties of an object such as position, scale, and rotation.
 /// </summary>
-public interface ITransform
+public interface ITransform : IAssignableGameObject, IEnumerable<ITransform>
 {
     /// <summary>
     /// Event triggered when the <see cref="Position"/> of the <see cref="ITransform"/> changes.
     /// </summary>
-    Action<ITransform>? OnPositionChanged { get; set; }
+    event OnPositionChangedDelegate? OnPositionChanged;
 
     /// <summary>
     /// Event triggered when the <see cref="Scale"/> of the <see cref="ITransform"/> changes.
     /// </summary>
-    Action<ITransform>? OnScaleChanged { get; set; }
+    event OnScaleChangedDelegate? OnScaleChanged;
 
     /// <summary>
     /// Event triggered when the <see cref="Rotation"/> of the <see cref="ITransform"/> changes.
     /// </summary>
-    Action<ITransform>? OnRotationChanged { get; set; }
+    event OnRotationChangedDelegate? OnRotationChanged;
 
     /// <summary>
-    /// The position of the <see cref="ITransform"/> in 2D space.
+    /// Event triggered when the <see cref="Parent"/> of the <see cref="ITransform"/> changes. The second parameter is the old <see cref="ITransform"/>.
+    /// </summary>
+    event OnParentChangedDelegate? OnParentChanged;
+
+    /// <summary>
+    /// Event triggered when a new <see cref="ITransform"/> is added to the <see cref="Children"/>.
+    /// </summary>
+    event OnChildrenAddedDelegate? OnChildrenAdded;
+
+    /// <summary>
+    /// Event triggered when an <see cref="ITransform"/> is removed from the <see cref="Children"/>.
+    /// </summary>
+    event OnChildrenRemovedDelegate? OnChildrenRemoved;
+
+    /// <summary>
+    /// The world position of the <see cref="ITransform"/> in 2D space.
     /// </summary>
     Vector2D Position { get; set; }
 
     /// <summary>
-    /// The scale of the <see cref="ITransform"/>.
+    /// The world scale of the <see cref="ITransform"/>.
     /// </summary>
     Vector2D Scale { get; set; }
 
     /// <summary>
-    /// The rotation of the <see cref="ITransform"/> in degrees.
+    /// The world rotation of the <see cref="ITransform"/> in degrees.
     /// </summary>
     float Rotation { get; set; }
+
+    /// <summary>
+    /// The local position of the <see cref="ITransform"/> in 2D space.
+    /// </summary>
+    Vector2D LocalPosition { get; set; }
+
+    /// <summary>
+    /// The local scale of the <see cref="ITransform"/>.
+    /// </summary>
+    Vector2D LocalScale { get; set; }
+
+    /// <summary>
+    /// The local rotation of the <see cref="ITransform"/> in degrees.
+    /// </summary>
+    float LocalRotation { get; set; }
+
+    /// <summary>
+    /// The parent <see cref="ITransform"/> of the <see cref="ITransform"/>.
+    /// </summary>
+    ITransform? Parent { get; }
+
+    /// <summary>
+    /// The <see cref="ITransform"/>s that have this <see cref="ITransform"/> as their <see cref="Parent"/>.
+    /// </summary>
+    IReadOnlyList<ITransform> Children { get; }
+
+    /// <summary>
+    /// Sets the parent <see cref="ITransform"/> of this <see cref="ITransform"/>.
+    /// </summary>
+    /// <param name="transform">The parent <see cref="ITransform"/> to set.</param>
+    void SetParent(ITransform? transform);
+
+    /// <summary>
+    /// Adds a child <see cref="ITransform"/> to this <see cref="ITransform"/>.
+    /// </summary>
+    /// <param name="transform">The child <see cref="ITransform"/> to add.</param>
+    void AddChild(ITransform transform);
+
+    /// <summary>
+    /// Removes a child <see cref="ITransform"/> from this <see cref="ITransform"/>.
+    /// </summary>
+    /// <param name="transform">The child <see cref="ITransform"/> to remove.</param>
+    void RemoveChild(ITransform transform);
+
+    delegate void OnPositionChangedDelegate(ITransform sender);
+    delegate void OnScaleChangedDelegate(ITransform sender);
+    delegate void OnRotationChangedDelegate(ITransform sender);
+    delegate void OnParentChangedDelegate(ITransform sender, ITransform? previousParent, ITransform? newParent);
+    delegate void OnChildrenAddedDelegate(ITransform sender, ITransform childrenAdded);
+    delegate void OnChildrenRemovedDelegate(ITransform sender, ITransform childrenRemoved);
 }

Engine.Core/Behaviour.cs

@@ -1,59 +1,105 @@
-using System;
-
 using Syntriax.Engine.Core.Abstract;
-using Syntriax.Engine.Core.Exceptions;
 
 namespace Syntriax.Engine.Core;
 
-[System.Diagnostics.DebuggerDisplay("{GetType().Name, nq}, Priority: {Priority}, Initialized: {Initialized}")]
+public abstract class Behaviour : BehaviourBase
-public abstract class Behaviour : BaseEntity, IBehaviour
 {
-    public Action<IAssignableBehaviourController>? OnBehaviourControllerAssigned { get; set; } = null;
+    private bool isInitializedThisFrame = false;
 
-    public Action<IBehaviour>? OnPriorityChanged { get; set; } = null;
+    protected IGameObject GameObject => BehaviourController.GameObject;
+    protected ITransform Transform => BehaviourController.GameObject.Transform;
 
-
+    public Behaviour()
-    private IBehaviourController _behaviourController = null!;
-
-    private int _priority = 0;
-
-    public IBehaviourController BehaviourController => _behaviourController;
-
-    public override bool IsActive => base.IsActive && BehaviourController.GameObject.StateEnable.Enabled;
-
-    public int Priority
     {
-        get => _priority;
+        OnInitialized += OnInitialize;
-        set
+        OnFinalized += OnFinalize;
+        OnUnassigned += OnUnassign;
+    }
+
+    protected virtual void OnUnassign() { }
+    private void OnUnassign(IAssignable assignable) => OnUnassign();
+
+    protected virtual void OnInitialize() { }
+    private void OnInitialize(IInitialize _)
     {
-            if (value == _priority)
+        isInitializedThisFrame = true;
+
+        BehaviourController.OnPreUpdate += PreUpdate;
+        BehaviourController.OnPreDraw += PreDraw;
+        BehaviourController.OnUpdate += Update;
+        BehaviourController.GameObject.OnEnteredHierarchy += EnteredHierarchy;
+        BehaviourController.GameObject.OnExitedHierarchy += ExitedHierarchy;
+
+        OnInitialize();
+
+        if (GameObject.IsInHierarchy)
+            EnteredHierarchy(GameObject, GameObject.GameManager ?? throw new System.Exception("Unexpected Error"));
+    }
+
+    protected virtual void OnFinalize() { }
+    private void OnFinalize(IInitialize _)
+    {
+        BehaviourController.OnPreUpdate -= PreUpdate;
+        BehaviourController.OnPreDraw -= PreDraw;
+        BehaviourController.OnUpdate -= Update;
+        BehaviourController.GameObject.OnEnteredHierarchy -= EnteredHierarchy;
+        BehaviourController.GameObject.OnExitedHierarchy -= ExitedHierarchy;
+
+        OnFinalize();
+
+        if (GameObject.IsInHierarchy)
+            ExitedHierarchy(GameObject, GameObject.GameManager ?? throw new System.Exception("Unexpected Error"));
+    }
+
+    protected virtual void OnPreUpdatePreActiveCheck() { }
+    protected virtual void OnPreUpdate() { }
+    private void PreUpdate(IBehaviourController _)
+    {
+        OnPreUpdatePreActiveCheck();
+
+        if (!IsActive)
             return;
 
-            _priority = value;
+        if (isInitializedThisFrame)
-            OnPriorityChanged?.Invoke(this);
+            FirstActiveFrame();
-        }
+
+        OnPreUpdate();
     }
 
-    public bool Assign(IBehaviourController behaviourController)
+    protected virtual void OnFirstActiveFrame() { }
+    private void FirstActiveFrame()
     {
-        if (Initialized)
+        OnFirstActiveFrame();
-            return false;
+        isInitializedThisFrame = false;
-
-        _behaviourController = behaviourController;
-        OnBehaviourControllerAssigned?.Invoke(this);
-        return true;
     }
 
-    protected override void UnassignInternal()
+    protected virtual void OnUpdatePreActiveCheck() { }
+    protected virtual void OnUpdate() { }
+    private void Update(IBehaviourController _)
     {
-        base.UnassignInternal();
+        OnUpdatePreActiveCheck();
-        _behaviourController = null!;
+
+        if (!IsActive)
+            return;
+
+        OnUpdate();
     }
 
-    protected override void InitializeInternal()
+    protected virtual void OnPreDrawPreActiveCheck() { }
+    protected virtual void OnPreDraw() { }
+    private void PreDraw(IBehaviourController _)
     {
-        base.InitializeInternal();
+        OnPreDrawPreActiveCheck();
-        NotAssignedException.Check(this, _behaviourController);
+
-        NotAssignedException.Check(this, StateEnable);
+        if (!StateEnable.Enabled)
+            return;
+
+        OnPreDraw();
     }
+
+    protected virtual void OnEnteredHierarchy(IGameManager gameManager) { }
+    private void EnteredHierarchy(IHierarchyObject sender, IGameManager gameManager) => OnEnteredHierarchy(gameManager);
+
+    protected virtual void OnExitedHierarchy(IGameManager gameManager) { }
+    private void ExitedHierarchy(IHierarchyObject sender, IGameManager gameManager) => OnExitedHierarchy(gameManager);
 }

Engine.Core/BehaviourBase.cs

@@ -0,0 +1,59 @@
+using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Core.Exceptions;
+
+namespace Syntriax.Engine.Core;
+
+[System.Diagnostics.DebuggerDisplay("{GetType().Name, nq}, Priority: {Priority}, Initialized: {Initialized}")]
+public abstract class BehaviourBase : BaseEntity, IBehaviour
+{
+    public event IAssignableBehaviourController.OnBehaviourControllerAssignedDelegate? OnBehaviourControllerAssigned = null;
+
+    public event IBehaviour.OnPriorityChangedDelegate? OnPriorityChanged = null;
+
+
+    private IBehaviourController _behaviourController = null!;
+
+    private int _priority = 0;
+
+
+    public IBehaviourController BehaviourController => _behaviourController;
+
+    public override bool IsActive => base.IsActive && BehaviourController.GameObject.StateEnable.Enabled;
+
+    public int Priority
+    {
+        get => _priority;
+        set
+        {
+            if (value == _priority)
+                return;
+
+            int previousPriority = _priority;
+            _priority = value;
+            OnPriorityChanged?.Invoke(this, previousPriority);
+        }
+    }
+
+    public bool Assign(IBehaviourController behaviourController)
+    {
+        if (IsInitialized)
+            return false;
+
+        _behaviourController = behaviourController;
+        OnBehaviourControllerAssigned?.Invoke(this);
+        return true;
+    }
+
+    protected override void UnassignInternal()
+    {
+        base.UnassignInternal();
+        _behaviourController = null!;
+    }
+
+    protected override void InitializeInternal()
+    {
+        base.InitializeInternal();
+        NotAssignedException.Check(this, _behaviourController);
+        NotAssignedException.Check(this, StateEnable);
+    }
+}

Engine.Core/BehaviourCollector.cs

@@ -6,13 +6,13 @@ using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
 
-public class BehaviourCacher<T> : IAssignableGameManager, IEnumerable<T>
+public class BehaviourCollector<T> : IAssignableGameManager, IEnumerable<T>
 {
-    public Action<IAssignable>? OnUnassigned { get; set; } = null;
+    public event IAssignable.OnUnassignedDelegate? OnUnassigned = null;
-    public Action<IAssignableGameManager>? OnGameManagerAssigned { get; set; } = null;
+    public event IAssignableGameManager.OnGameManagerAssignedDelegate? OnGameManagerAssigned = null;
 
-    public Action<BehaviourCacher<T>, T>? OnCached { get; set; } = null;
+    public event OnCollectedDelegate? OnCollected = null;
-    public Action<BehaviourCacher<T>, T>? OnUncached { get; set; } = null;
+    public event OnRemovedDelegate? OnRemoved = null;
 
     private readonly List<T> _behaviours = new(32);
 
@@ -21,19 +21,25 @@ public class BehaviourCacher<T> : IAssignableGameManager, IEnumerable<T>
 
     public T this[Index index] => _behaviours[index];
 
-    public BehaviourCacher() { }
+    public BehaviourCollector() { }
-    public BehaviourCacher(IGameManager gameManager) => Assign(gameManager);
+    public BehaviourCollector(IGameManager gameManager) => Assign(gameManager);
 
     private void OnGameObjectRegistered(IGameManager manager, IGameObject gameObject)
     {
         gameObject.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
         gameObject.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
+
+        foreach (IBehaviour item in gameObject.BehaviourController)
+            OnBehaviourAdded(gameObject.BehaviourController, item);
     }
 
     private void OnGameObjectUnregistered(IGameManager manager, IGameObject gameObject)
     {
         gameObject.BehaviourController.OnBehaviourAdded -= OnBehaviourAdded;
         gameObject.BehaviourController.OnBehaviourRemoved -= OnBehaviourRemoved;
+
+        foreach (IBehaviour item in gameObject.BehaviourController)
+            OnBehaviourRemoved(gameObject.BehaviourController, item);
     }
 
     private void OnBehaviourAdded(IBehaviourController controller, IBehaviour behaviour)
@@ -42,7 +48,7 @@ public class BehaviourCacher<T> : IAssignableGameManager, IEnumerable<T>
             return;
 
         _behaviours.Add(tBehaviour);
-        OnCached?.Invoke(this, tBehaviour);
+        OnCollected?.Invoke(this, tBehaviour);
     }
 
     private void OnBehaviourRemoved(IBehaviourController controller, IBehaviour behaviour)
@@ -53,7 +59,7 @@ public class BehaviourCacher<T> : IAssignableGameManager, IEnumerable<T>
         if (!_behaviours.Remove(tBehaviour))
             return;
 
-        OnUncached?.Invoke(this, tBehaviour);
+        OnRemoved?.Invoke(this, tBehaviour);
     }
 
     public bool Assign(IGameManager gameManager)
@@ -62,11 +68,7 @@ public class BehaviourCacher<T> : IAssignableGameManager, IEnumerable<T>
             return false;
 
         foreach (IGameObject gameObject in gameManager)
-        {
             OnGameObjectRegistered(gameManager, gameObject);
-            foreach (IBehaviour behaviour in gameObject.BehaviourController)
-                OnBehaviourAdded(gameObject.BehaviourController, behaviour);
-        }
 
         gameManager.OnGameObjectRegistered += OnGameObjectRegistered;
         gameManager.OnGameObjectUnRegistered += OnGameObjectUnregistered;
@@ -83,11 +85,7 @@ public class BehaviourCacher<T> : IAssignableGameManager, IEnumerable<T>
             return false;
 
         foreach (IGameObject gameObject in GameManager)
-        {
             OnGameObjectUnregistered(GameManager, gameObject);
-            foreach (IBehaviour behaviour in gameObject.BehaviourController)
-                OnBehaviourRemoved(gameObject.BehaviourController, behaviour);
-        }
 
         GameManager.OnGameObjectRegistered -= OnGameObjectRegistered;
         GameManager.OnGameObjectUnRegistered -= OnGameObjectUnregistered;
@@ -99,4 +97,8 @@ public class BehaviourCacher<T> : IAssignableGameManager, IEnumerable<T>
 
     public IEnumerator<T> GetEnumerator() => _behaviours.GetEnumerator();
     IEnumerator IEnumerable.GetEnumerator() => _behaviours.GetEnumerator();
+
+
+    public delegate void OnCollectedDelegate(BehaviourCollector<T> sender, T behaviourCollected);
+    public delegate void OnRemovedDelegate(BehaviourCollector<T> sender, T behaviourRemoved);
 }

Engine.Core/BehaviourController.cs

@@ -5,33 +5,57 @@ using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 
 using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Core.Exceptions;
 
 namespace Syntriax.Engine.Core;
 
 [System.Diagnostics.DebuggerDisplay("Behaviour Count: {behaviours.Count}")]
 public class BehaviourController : IBehaviourController
 {
-    public Action<IBehaviourController>? OnPreUpdate { get; set; }
+    public event IBehaviourController.OnPreUpdateDelegate? OnPreUpdate = null;
-    public Action<IBehaviourController>? OnUpdate { get; set; } = null;
+    public event IBehaviourController.OnUpdateDelegate? OnUpdate = null;
-    public Action<IBehaviourController>? OnPreDraw { get; set; } = null;
+    public event IBehaviourController.OnPreDrawDelegate? OnPreDraw = null;
 
-    public Action<IBehaviourController, IBehaviour>? OnBehaviourAdded { get; set; } = null;
+    public event IBehaviourController.OnBehaviourAddedDelegate? OnBehaviourAdded = null;
-    public Action<IBehaviourController, IBehaviour>? OnBehaviourRemoved { get; set; } = null;
+    public event IBehaviourController.OnBehaviourRemovedDelegate? OnBehaviourRemoved = null;
-    public Action<IAssignable>? OnUnassigned { get; set; } = null;
+    public event IAssignableGameObject.OnGameObjectAssignedDelegate? OnGameObjectAssigned = null;
-    public Action<IAssignableGameObject>? OnGameObjectAssigned { get; set; } = null;
 
+    public event IInitialize.OnInitializedDelegate? OnInitialized = null;
+    public event IInitialize.OnFinalizedDelegate? OnFinalized = null;
+
+    public event IAssignable.OnUnassignedDelegate? OnUnassigned = null;
 
     private readonly IList<IBehaviour> behaviours = new List<IBehaviour>(Constants.BEHAVIOURS_SIZE_INITIAL);
 
     private IGameObject _gameObject = null!;
-
+    private bool _initialized = false;
 
     public IGameObject GameObject => _gameObject;
 
+
+    public bool IsInitialized
+    {
+        get => _initialized;
+        private set
+        {
+            if (value == _initialized)
+                return;
+
+            _initialized = value;
+            if (value)
+                OnInitialized?.Invoke(this);
+            else
+                OnFinalized?.Invoke(this);
+        }
+    }
+
     public T AddBehaviour<T>(T behaviour) where T : class, IBehaviour
     {
         InsertBehaviourByPriority(behaviour);
 
+        behaviour.Assign(this);
+        behaviour.Assign(GameObject.StateEnable);
+
         behaviour.Initialize();
         behaviour.OnPriorityChanged += OnPriorityChange;
         OnBehaviourAdded?.Invoke(this, behaviour);
@@ -110,7 +134,7 @@ public class BehaviourController : IBehaviourController
 
     public bool Assign(IGameObject gameObject)
     {
-        if (GameObject is not null && GameObject.Initialized)
+        if (GameObject is not null && GameObject.IsInitialized)
             return false;
 
         _gameObject = gameObject;
@@ -118,9 +142,36 @@ public class BehaviourController : IBehaviourController
         return true;
     }
 
+
+    public bool Initialize()
+    {
+        if (IsInitialized)
+            return false;
+
+        NotAssignedException.Check(this, _gameObject);
+
+        foreach (IBehaviour behaviour in behaviours)
+            behaviour.Initialize();
+
+        IsInitialized = true;
+        return true;
+    }
+
+    public bool Finalize()
+    {
+        if (!IsInitialized)
+            return false;
+
+        foreach (IBehaviour behaviour in behaviours)
+            behaviour.Finalize();
+
+        IsInitialized = false;
+        return true;
+    }
+
     public bool Unassign()
     {
-        if (GameObject is not null && GameObject.Initialized)
+        if (IsInitialized)
             return false;
 
         _gameObject = null!;
@@ -165,10 +216,11 @@ public class BehaviourController : IBehaviourController
             behaviours.Add(behaviour);
     }
 
-    private void OnPriorityChange(IBehaviour behaviour)
+
+    private void OnPriorityChange(IBehaviour sender, int previousPriority)
     {
-        behaviours.Remove(behaviour);
+        behaviours.Remove(sender);
-        InsertBehaviourByPriority(behaviour);
+        InsertBehaviourByPriority(sender);
     }
 
     public IEnumerator<IBehaviour> GetEnumerator() => behaviours.GetEnumerator();

Engine.Core/BehaviourOverride.cs

@@ -1,87 +0,0 @@
-using Syntriax.Engine.Core.Abstract;
-
-namespace Syntriax.Engine.Core;
-
-public abstract class BehaviourOverride : Behaviour
-{
-    private bool isInitializedThisFrame = false;
-
-    protected IGameObject GameObject => BehaviourController.GameObject;
-    protected ITransform Transform => BehaviourController.GameObject.Transform;
-
-    public BehaviourOverride()
-    {
-        OnInitialized += OnInitialize;
-        OnFinalized += OnFinalize;
-        OnUnassigned += OnUnassign;
-    }
-
-    protected virtual void OnUnassign() { }
-    private void OnUnassign(IAssignable assignable) => OnUnassign();
-
-    protected virtual void OnInitialize() { }
-    private void OnInitialize(IInitialize _)
-    {
-        isInitializedThisFrame = true;
-
-        BehaviourController.OnPreUpdate += PreUpdate;
-        BehaviourController.OnPreDraw += PreDraw;
-        BehaviourController.OnUpdate += Update;
-        OnInitialize();
-    }
-
-    protected virtual void OnFinalize() { }
-    private void OnFinalize(IInitialize _)
-    {
-        BehaviourController.OnPreUpdate -= PreUpdate;
-        BehaviourController.OnPreDraw -= PreDraw;
-        BehaviourController.OnUpdate -= Update;
-        OnFinalize();
-    }
-
-    protected virtual void OnPreUpdatePreActiveCheck() { }
-    protected virtual void OnPreUpdate() { }
-    private void PreUpdate(IBehaviourController _)
-    {
-        OnPreUpdatePreActiveCheck();
-
-        if (!IsActive)
-            return;
-
-        if (isInitializedThisFrame)
-            FirstActiveFrame();
-
-        OnPreUpdate();
-    }
-
-    protected virtual void OnFirstActiveFrame() { }
-    private void FirstActiveFrame()
-    {
-        OnFirstActiveFrame();
-        isInitializedThisFrame = false;
-    }
-
-    protected virtual void OnUpdatePreActiveCheck() { }
-    protected virtual void OnUpdate() { }
-    private void Update(IBehaviourController _)
-    {
-        OnUpdatePreActiveCheck();
-
-        if (!IsActive)
-            return;
-
-        OnUpdate();
-    }
-
-    protected virtual void OnPreDrawPreActiveCheck() { }
-    protected virtual void OnPreDraw() { }
-    private void PreDraw(IBehaviourController _)
-    {
-        OnPreDrawPreActiveCheck();
-
-        if (!StateEnable.Enabled)
-            return;
-
-        OnPreDraw();
-    }
-}

Engine.Core/CoroutineManager.cs

@@ -0,0 +1,44 @@
+using System.Collections;
+using System.Collections.Generic;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public class CoroutineManager : HierarchyObjectBase
+{
+    private readonly List<IEnumerator> enumerators = [];
+
+    public IEnumerator CreateCoroutine(IEnumerator enumerator)
+    {
+        enumerators.Add(enumerator);
+        return enumerator;
+    }
+
+    public void StopCoroutine(IEnumerator enumerator)
+    {
+        enumerators.Remove(enumerator);
+    }
+
+    protected override void OnEnteringHierarchy(IGameManager gameManager)
+    {
+        gameManager.OnUpdate += OnUpdate;
+    }
+
+    protected override void OnExitingHierarchy(IGameManager gameManager)
+    {
+        gameManager.OnUpdate -= OnUpdate;
+    }
+
+    private void OnUpdate(IGameManager sender, EngineTime time)
+    {
+        for (int i = enumerators.Count - 1; i >= 0; i--)
+        {
+            if (enumerators[i].Current is ICoroutineYield coroutineYield && coroutineYield.Yield())
+                continue;
+
+            if (!enumerators[i].MoveNext())
+                enumerators.RemoveAt(i);
+        }
+    }
+}

Engine.Core/CoroutineYield.cs

@@ -0,0 +1,12 @@
+using System;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public class CoroutineYield(Func<bool> condition) : ICoroutineYield
+{
+    private readonly Func<bool> condition = condition;
+
+    public bool Yield() => condition.Invoke();
+}

Engine.Core/EngineTime.cs

@@ -7,5 +7,5 @@ public readonly struct EngineTime(TimeSpan Total, TimeSpan Elapsed)
     public readonly TimeSpan Total = Total;
     public readonly TimeSpan Elapsed = Elapsed;
 
-    public readonly float DeltaTimeFrame = (float)Elapsed.TotalMilliseconds;
+    public readonly float DeltaTimeFrame = (float)Elapsed.TotalMilliseconds * .001f;
 }

Engine.Core/Extensions/BehaviourControllerExtensions.cs

@@ -0,0 +1,47 @@
+using System.Diagnostics.CodeAnalysis;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public static class BehaviourControllerExtensions
+{
+    public static bool TryGetBehaviourInParent<T>(this IBehaviourController behaviourController, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
+    {
+        behaviour = GetBehaviourInParent<T>(behaviourController);
+        return behaviour is not null;
+    }
+
+    public static T? GetBehaviourInParent<T>(this IBehaviourController behaviourController) where T : class
+    {
+        IBehaviourController? controller = behaviourController;
+
+        while (controller is not null)
+        {
+            if (behaviourController.GetBehaviour<T>() is T behaviour)
+                return behaviour;
+
+            controller = controller.GameObject.Transform.Parent?.GameObject.BehaviourController;
+        }
+
+        return default;
+    }
+
+    public static bool TryGetBehaviourInChildren<T>(this IBehaviourController behaviourController, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
+    {
+        behaviour = GetBehaviourInChildren<T>(behaviourController);
+        return behaviour is not null;
+    }
+
+    public static T? GetBehaviourInChildren<T>(this IBehaviourController behaviourController) where T : class
+    {
+        if (behaviourController.GetBehaviour<T>() is T localBehaviour)
+            return localBehaviour;
+
+        foreach (ITransform transform in behaviourController.GameObject.Transform)
+            if (GetBehaviourInChildren<T>(transform.GameObject.BehaviourController) is T behaviour)
+                return behaviour;
+
+        return default;
+    }
+}

Engine.Core/Extensions/BehaviourExtensions.cs

@@ -7,18 +7,22 @@ namespace Syntriax.Engine.Core;
 
 public static class BehaviourExtensions
 {
-    public static bool TryFindBehaviour<T>(this IEnumerable<IGameObject> gameObjects, [NotNullWhen(returnValue: true)] out T? behaviour)
+    public static T? FindBehaviour<T>(this IEnumerable<IGameObject> gameObjects) where T : class
     {
-        behaviour = default;
-
         foreach (IGameObject gameObject in gameObjects)
-            if (gameObject.BehaviourController.TryGetBehaviour(out behaviour))
+            if (gameObject.BehaviourController.TryGetBehaviour(out T? behaviour))
-                return true;
+                return behaviour;
 
-        return false;
+        return default;
     }
 
-    public static void FindBehaviours<T>(this IEnumerable<IGameObject> gameObjects, List<T> behaviours)
+    public static bool TryFindBehaviour<T>(this IEnumerable<IGameObject> gameObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
+    {
+        behaviour = FindBehaviour<T>(gameObjects);
+        return behaviour is not null;
+    }
+
+    public static void FindBehaviours<T>(this IEnumerable<IGameObject> gameObjects, List<T> behaviours) where T : class
     {
         behaviours.Clear();
         List<T> cache = [];

Engine.Core/Extensions/HierarchyObjectExtensions.cs

@@ -0,0 +1,32 @@
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public static class HierarchyObjectExtensions
+{
+    public static T? FindObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects) where T : class
+    {
+        foreach (IHierarchyObject hierarchyObject in hierarchyObjects)
+            if (hierarchyObject is T @object)
+                return @object;
+
+        return default;
+    }
+
+    public static bool TryFindObject<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
+    {
+        behaviour = FindObject<T>(hierarchyObjects);
+        return behaviour is not null;
+    }
+
+    public static void FindObjects<T>(this IEnumerable<IHierarchyObject> hierarchyObjects, List<T> behaviours) where T : class
+    {
+        behaviours.Clear();
+        foreach (IHierarchyObject hierarchyObject in hierarchyObjects)
+            if (hierarchyObject is T @object)
+                behaviours.Add(@object);
+    }
+}

Engine.Core/Extensions/TransformExtensions.cs

@@ -4,11 +4,16 @@ namespace Syntriax.Engine.Core;
 
 public static class TransformExtensions
 {
-    public static ITransform SetTransform(this ITransform transform, Vector2D? position = null, float? rotation = null, Vector2D? scale = null)
+    public static ITransform SetTransform(this ITransform transform,
+        Vector2D? position = null, float? rotation = null, Vector2D? scale = null,
+        Vector2D? localPosition = null, float? localRotation = null, Vector2D? localScale = null)
     {
         if (position.HasValue) transform.Position = position.Value;
         if (rotation.HasValue) transform.Rotation = rotation.Value;
         if (scale.HasValue) transform.Scale = scale.Value;
+        if (localPosition.HasValue) transform.LocalPosition = localPosition.Value;
+        if (localRotation.HasValue) transform.LocalRotation = localRotation.Value;
+        if (localScale.HasValue) transform.LocalScale = localScale.Value;
         return transform;
     }
 }

Engine.Core/Factory/GameObjectFactory.cs

@@ -22,6 +22,9 @@ public class GameObjectFactory
         behaviourController ??= TypeFactory.Get<BehaviourController>();
         stateEnable ??= TypeFactory.Get<StateEnable>();
 
+        if (!transform.Assign(gameObject))
+            throw AssignException.From(transform, gameObject);
+
         if (!behaviourController.Assign(gameObject))
             throw AssignException.From(behaviourController, gameObject);
         if (!stateEnable.Assign(gameObject))

Engine.Core/GameManager.cs

@@ -11,11 +11,16 @@ namespace Syntriax.Engine.Core;
 [System.Diagnostics.DebuggerDisplay("GameObject Count: {_gameObjects.Count}")]
 public class GameManager : BaseEntity, IGameManager
 {
-    public Action<IGameManager, IGameObject>? OnGameObjectRegistered { get; set; } = null;
+    public event IGameManager.OnUpdateDelegate? OnUpdate = null;
-    public Action<IGameManager, IGameObject>? OnGameObjectUnRegistered { get; set; } = null;
+    public event IGameManager.OnPreDawDelegate? OnPreDraw = null;
 
+    public event IGameManager.OnGameObjectRegisteredDelegate? OnGameObjectRegistered = null;
+    public event IGameManager.OnGameObjectUnRegisteredDelegate? OnGameObjectUnRegistered = null;
+    public event IGameManager.OnHierarchyObjectRegisteredDelegate? OnHierarchyObjectRegistered = null;
+    public event IGameManager.OnHierarchyObjectUnRegisteredDelegate? OnHierarchyObjectUnRegistered = null;
 
     private readonly List<IGameObject> _gameObjects = new(Constants.GAME_OBJECTS_SIZE_INITIAL);
+    private readonly List<IHierarchyObject> _hierarchyObjects = new(Constants.GAME_OBJECTS_SIZE_INITIAL);
 
     private GameObjectFactory _gameObjectFactory = null!;
 
@@ -30,6 +35,7 @@ public class GameManager : BaseEntity, IGameManager
     }
 
     public IReadOnlyList<IGameObject> GameObjects => _gameObjects;
+    public IReadOnlyList<IHierarchyObject> HierarchyObjects => _hierarchyObjects;
 
     public override IStateEnable StateEnable
     {
@@ -46,12 +52,23 @@ public class GameManager : BaseEntity, IGameManager
         }
     }
 
-    public void RegisterGameObject(IGameObject gameObject)
+    public void Register(IHierarchyObject hierarchyObject)
     {
-        if (_gameObjects.Contains(gameObject))
+        if (_hierarchyObjects.Contains(hierarchyObject))
-            throw new Exception($"{nameof(IGameObject)} named {gameObject.Name} is already registered to the {nameof(GameManager)}.");
+            throw new Exception($"{nameof(IHierarchyObject)} named {hierarchyObject.Name} is already registered to the {nameof(GameManager)}.");
 
+        if (hierarchyObject is IGameObject gameObject)
             Register(gameObject);
+        else
+        {
+            if (!hierarchyObject.Initialize())
+                throw new Exception($"{nameof(hierarchyObject)} can't be initialized");
+
+            _hierarchyObjects.Add(hierarchyObject);
+            hierarchyObject.EnterHierarchy(this);
+
+            OnHierarchyObjectRegistered?.Invoke(this, hierarchyObject);
+        }
     }
 
     public T InstantiateGameObject<T>(params object?[]? args) where T : class, IGameObject
@@ -61,13 +78,23 @@ public class GameManager : BaseEntity, IGameManager
         return gameObject;
     }
 
-    public IGameObject RemoveGameObject(IGameObject gameObject)
+    public void Remove(IHierarchyObject hierarchyObject)
     {
-        if (!_gameObjects.Contains(gameObject))
+        if (!_hierarchyObjects.Contains(hierarchyObject))
-            throw new Exception($"{nameof(IGameObject)} named {gameObject.Name} is not registered to the {nameof(GameManager)}.");
+            throw new Exception($"{nameof(IHierarchyObject)} named {hierarchyObject.Name} is not registered to the {nameof(GameManager)}.");
 
+        if (hierarchyObject is IGameObject gameObject)
             Unregister(gameObject);
-        return gameObject;
+        else
+        {
+            _hierarchyObjects.Remove(hierarchyObject);
+            hierarchyObject.ExitHierarchy();
+
+            if (!hierarchyObject.Finalize())
+                throw new Exception($"{nameof(hierarchyObject)} can't be finalized");
+
+            OnHierarchyObjectUnRegistered?.Invoke(this, hierarchyObject);
+        }
     }
 
     protected override void InitializeInternal()
@@ -89,33 +116,67 @@ public class GameManager : BaseEntity, IGameManager
     public void Update(EngineTime time)
     {
         Time.SetTime(time);
-        foreach (var gameObject in GameObjects)
+        for (int i = 0; i < GameObjects.Count; i++)
-            gameObject.BehaviourController.Update();
+            GameObjects[i].BehaviourController.Update();
+
+        OnUpdate?.Invoke(this, time);
     }
 
     public void PreDraw()
     {
-        foreach (var gameObject in GameObjects)
+        for (int i = 0; i < GameObjects.Count; i++)
-            gameObject.BehaviourController.UpdatePreDraw();
+            GameObjects[i].BehaviourController.UpdatePreDraw();
+
+        OnPreDraw?.Invoke(this);
     }
 
     /////////////////////////////////////////////////////////////////
 
     private void Register(IGameObject gameObject)
     {
-        gameObject.Assign(this);
+        if (_gameObjects.Contains(gameObject))
+            throw new Exception($"{nameof(IGameObject)} named {gameObject.Name} is already registered to the {nameof(GameManager)}.");
 
         gameObject.OnFinalized += OnGameObjectFinalize;
+        gameObject.OnExitedHierarchy += OnGameObjectExitedHierarchy;
+
+        if (!gameObject.Initialize())
+            throw new Exception($"{nameof(gameObject)} can't be initialized");
+
+        foreach (ITransform child in gameObject.Transform.Children)
+            Register(child.GameObject);
 
         _gameObjects.Add(gameObject);
+        _hierarchyObjects.Add(gameObject);
+
+        if (!gameObject.EnterHierarchy(this))
+            throw new Exception($"{nameof(gameObject)} can't enter the hierarchy");
+
+        OnHierarchyObjectRegistered?.Invoke(this, gameObject);
         OnGameObjectRegistered?.Invoke(this, gameObject);
     }
 
     private void Unregister(IGameObject gameObject)
     {
+        if (!_gameObjects.Contains(gameObject))
+            throw new Exception($"{nameof(IGameObject)} named {gameObject.Name} is not registered to the {nameof(GameManager)}.");
+
         gameObject.OnFinalized -= OnGameObjectFinalize;
+        gameObject.OnExitedHierarchy -= OnGameObjectExitedHierarchy;
+
+        foreach (ITransform child in gameObject.Transform.Children)
+            Unregister(child.GameObject);
 
         _gameObjects.Remove(gameObject);
+        _hierarchyObjects.Remove(gameObject);
+
+        if (!gameObject.ExitHierarchy())
+            throw new Exception($"{nameof(gameObject)} can't exit the hierarchy");
+
+        if (!gameObject.Finalize())
+            throw new Exception($"{nameof(gameObject)} can't be finalized");
+
+        OnHierarchyObjectUnRegistered?.Invoke(this, gameObject);
         OnGameObjectUnRegistered?.Invoke(this, gameObject);
     }
 
@@ -125,6 +186,12 @@ public class GameManager : BaseEntity, IGameManager
             Unregister(gameObject);
     }
 
+    private void OnGameObjectExitedHierarchy(IHierarchyObject sender, IGameManager gameManager)
+    {
+        if (sender is IGameObject gameObject)
+            Unregister(gameObject);
+    }
+
     /////////////////////////////////////////////////////////////////
 
     public IEnumerator<IGameObject> GetEnumerator() => _gameObjects.GetEnumerator();

Engine.Core/GameObject.cs

@@ -1,5 +1,3 @@
-using System;
-
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Core.Exceptions;
 
@@ -8,25 +6,26 @@ namespace Syntriax.Engine.Core;
 [System.Diagnostics.DebuggerDisplay("Name: {Name}, Initialized: {Initialized}")]
 public class GameObject : BaseEntity, IGameObject
 {
-    public Action<IAssignableTransform>? OnTransformAssigned { get; set; } = null;
+    public event IHierarchyObject.OnEnteredHierarchyDelegate? OnEnteredHierarchy = null;
-    public Action<IAssignableBehaviourController>? OnBehaviourControllerAssigned { get; set; } = null;
+    public event IHierarchyObject.OnExitedHierarchyDelegate? OnExitedHierarchy = null;
-    public Action<IAssignableGameManager>? OnGameManagerAssigned { get; set; } = null;
 
-    public Action<IEntity>? OnNameChanged { get; set; } = null;
+    public event IAssignableTransform.OnTransformAssignedDelegate? OnTransformAssigned = null;
+    public event IAssignableBehaviourController.OnBehaviourControllerAssignedDelegate? OnBehaviourControllerAssigned = null;
 
-    public Action<IGameObject>? OnUpdated { get; set; } = null;
+    public event INameable.OnNameChangedDelegate? OnNameChanged = null;
 
+    public event IGameObject.OnUpdatedDelegate? OnUpdated = null;
 
     private ITransform _transform = null!;
     private IBehaviourController _behaviourController = null!;
-    private IStateEnable _stateEnable = null!;
+    private IGameManager? _gameManager = null;
-    private IGameManager _gameManager = null!;
 
     private string _name = nameof(GameObject);
 
     public ITransform Transform => _transform;
     public IBehaviourController BehaviourController => _behaviourController;
-    public IGameManager GameManager => _gameManager;
+    public IGameManager? GameManager => _gameManager;
+    public bool IsInHierarchy => GameManager is not null;
 
     public string Name
     {
@@ -35,8 +34,9 @@ public class GameObject : BaseEntity, IGameObject
         {
             if (value == _name) return;
 
+            string previousName = _name;
             _name = value;
-            OnNameChanged?.Invoke(this);
+            OnNameChanged?.Invoke(this, previousName);
         }
     }
 
@@ -46,13 +46,14 @@ public class GameObject : BaseEntity, IGameObject
 
         NotAssignedException.Check(this, _transform);
         NotAssignedException.Check(this, _behaviourController);
-        NotAssignedException.Check(this, _stateEnable);
+
-        NotAssignedException.Check(this, _gameManager);
+        if (!_behaviourController.Initialize())
+            throw new System.Exception($"Failed to Initialize {BehaviourController.GetType().Name} on {Transform.GameObject.Name}");
     }
 
     public void Update()
     {
-        if (!_stateEnable.Enabled)
+        if (!StateEnable.Enabled)
             return;
 
         OnUpdated?.Invoke(this);
@@ -62,23 +63,25 @@ public class GameObject : BaseEntity, IGameObject
     {
         base.FinalizeInternal();
 
-        foreach (IBehaviour behaviour in _behaviourController.GetBehaviours<IBehaviour>())
+        if (!_behaviourController.Finalize())
-            behaviour.Finalize();
+            throw new System.Exception($"Failed to Finalize {BehaviourController.GetType().Name} on {Transform.GameObject.Name}");
     }
 
     public bool Assign(ITransform transform)
     {
-        if (Initialized)
+        if (IsInitialized)
             return false;
 
         _transform = transform;
         OnTransformAssigned?.Invoke(this);
+        transform.OnParentChanged += OnParentChangedInternal;
+        OnParentChangedInternal(transform, null, transform.Parent);
         return true;
     }
 
     public bool Assign(IBehaviourController behaviourController)
     {
-        if (Initialized)
+        if (IsInitialized)
             return false;
 
         _behaviourController = behaviourController;
@@ -86,32 +89,63 @@ public class GameObject : BaseEntity, IGameObject
         return true;
     }
 
-    public bool Assign(IGameManager gameManager)
-    {
-        if (Initialized)
-            return false;
-
-        _gameManager = gameManager;
-        OnGameManagerAssigned?.Invoke(this);
-        return true;
-    }
-
     protected override void UnassignInternal()
     {
         base.UnassignInternal();
 
-        _stateEnable = null!;
+        _transform.OnParentChanged -= OnParentChangedInternal;
+        OnParentChangedInternal(_transform, _transform.Parent, null);
         _transform = null!;
         _behaviourController = null!;
         _gameManager = null!;
     }
 
     public GameObject() { OnBehaviourControllerAssigned += ConnectBehaviourController; }
+
     private void ConnectBehaviourController(IAssignableBehaviourController controller)
     {
         controller.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
         controller.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
     }
-    private void OnBehaviourRemoved(IBehaviourController _, IBehaviour behaviour) { if (Initialized) behaviour.Initialize(); }
+    private void OnBehaviourRemoved(IBehaviourController _, IBehaviour behaviour) { if (IsInitialized) behaviour.Finalize(); }
-    private void OnBehaviourAdded(IBehaviourController _, IBehaviour behaviour) { if (Initialized) behaviour.Finalize(); }
+    private void OnBehaviourAdded(IBehaviourController _, IBehaviour behaviour) { if (!IsInitialized) behaviour.Initialize(); }
+
+    private void OnParentChangedInternal(ITransform sender, ITransform? previousParent, ITransform? newParent)
+    {
+        if (previousParent is not null)
+        {
+            previousParent.OnParentChanged -= OnParentChangedInternal;
+            previousParent.GameObject.OnEnteredHierarchy -= EnterHierarchyInternal;
+            previousParent.GameObject.OnExitedHierarchy -= ExitHierarchyInternal;
+        }
+        if (newParent is not null)
+        {
+            newParent.OnParentChanged += OnParentChangedInternal;
+            newParent.GameObject.OnEnteredHierarchy += EnterHierarchyInternal;
+            newParent.GameObject.OnExitedHierarchy += ExitHierarchyInternal;
+        }
+    }
+
+    private void EnterHierarchyInternal(IHierarchyObject sender, IGameManager gameManager) => ((IHierarchyObject)this).EnterHierarchy(gameManager);
+    private void ExitHierarchyInternal(IHierarchyObject sender, IGameManager gameManager) => ((IHierarchyObject)this).ExitHierarchy();
+
+    bool IHierarchyObject.EnterHierarchy(IGameManager gameManager)
+    {
+        if (IsInHierarchy)
+            return false;
+
+        _gameManager = gameManager;
+        OnEnteredHierarchy?.Invoke(this, gameManager);
+        return true;
+    }
+
+    bool IHierarchyObject.ExitHierarchy()
+    {
+        if (!IsInHierarchy || _gameManager is not IGameManager gameManager)
+            return false;
+
+        _gameManager = null;
+        OnExitedHierarchy?.Invoke(this, gameManager);
+        return true;
+    }
 }

Engine.Core/HierarchyObjectBase.cs

@@ -0,0 +1,142 @@
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Core;
+
+public abstract class HierarchyObjectBase : IHierarchyObject
+{
+    public event IHierarchyObject.OnEnteredHierarchyDelegate? OnEnteredHierarchy = null;
+    public event IHierarchyObject.OnExitedHierarchyDelegate? OnExitedHierarchy = null;
+    public event IEntity.OnIdChangedDelegate? OnIdChanged = null;
+    public event IInitialize.OnInitializedDelegate? OnInitialized = null;
+    public event IInitialize.OnFinalizedDelegate? OnFinalized = null;
+    public event IAssignableStateEnable.OnStateEnableAssignedDelegate? OnStateEnableAssigned = null;
+    public event IAssignable.OnUnassignedDelegate? OnUnassigned = null;
+    public event INameable.OnNameChangedDelegate? OnNameChanged = null;
+
+    private string _id = string.Empty;
+    private string _name = nameof(HierarchyObjectBase);
+    private bool _initialized = false;
+    private IStateEnable _stateEnable = null!;
+    private IGameManager? _gameManager = null;
+
+    public IGameManager? GameManager => _gameManager;
+
+    public bool IsInHierarchy => _gameManager is not null;
+
+    public bool IsInitialized
+    {
+        get => _initialized;
+        private set
+        {
+            if (value == _initialized)
+                return;
+
+            _initialized = value;
+            if (value)
+                OnInitialized?.Invoke(this);
+            else
+                OnFinalized?.Invoke(this);
+        }
+    }
+
+    public virtual IStateEnable StateEnable => _stateEnable;
+
+    public string Name
+    {
+        get => _name;
+        set
+        {
+            if (value == _name) return;
+
+            string previousName = _name;
+            _name = value;
+            OnNameChanged?.Invoke(this, previousName);
+        }
+    }
+
+    public string Id
+    {
+        get => _id;
+        set
+        {
+            if (value == _id)
+                return;
+
+            string previousId = _id;
+
+            _id = value;
+            OnIdChanged?.Invoke(this, previousId);
+        }
+    }
+
+    public bool Assign(IStateEnable stateEnable)
+    {
+        if (IsInitialized)
+            return false;
+
+        _stateEnable = stateEnable;
+        _stateEnable.Assign(this);
+        OnStateEnableAssigned?.Invoke(this);
+        return true;
+    }
+
+    protected virtual void UnassignInternal() { }
+    public bool Unassign()
+    {
+        if (IsInitialized)
+            return false;
+
+        UnassignInternal();
+
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
+
+    protected virtual void InitializeInternal() { }
+    public bool Initialize()
+    {
+        if (IsInitialized)
+            return false;
+
+        InitializeInternal();
+
+        IsInitialized = true;
+        return true;
+    }
+
+    protected virtual void FinalizeInternal() { }
+    public bool Finalize()
+    {
+        if (!IsInitialized)
+            return false;
+
+        FinalizeInternal();
+
+        IsInitialized = false;
+        return true;
+    }
+
+    protected virtual void OnEnteringHierarchy(IGameManager gameManager) { }
+    bool IHierarchyObject.EnterHierarchy(IGameManager gameManager)
+    {
+        if (IsInHierarchy)
+            return false;
+
+        _gameManager = gameManager;
+        OnEnteringHierarchy(gameManager);
+        OnEnteredHierarchy?.Invoke(this, gameManager);
+        return true;
+    }
+
+    protected virtual void OnExitingHierarchy(IGameManager gameManager) { }
+    bool IHierarchyObject.ExitHierarchy()
+    {
+        if (!IsInHierarchy || _gameManager is not IGameManager gameManager)
+            return false;
+
+        _gameManager = null;
+        OnExitingHierarchy(gameManager);
+        OnExitedHierarchy?.Invoke(this, gameManager);
+        return true;
+    }
+}

Engine.Core/Math.cs

@@ -4,7 +4,8 @@ using System.Numerics;
 namespace Syntriax.Engine.Core;
 
 public static class Math
-{/// <summary>
+{
+    /// <summary>
     /// The value of Pi (π), a mathematical constant approximately equal to 3.14159.
     /// </summary>
     public const float PI = 3.1415926535897932f;
@@ -37,6 +38,20 @@ public static class Math
     /// <returns>The absolute value of <paramref name="x"/>.</returns>
     public static T Abs<T>(T x) where T : INumber<T> => x > T.Zero ? x : -x;
 
+    /// <summary>
+    /// Returns the cosine of a number.
+    /// </summary>
+    /// <param name="x">The number.</param>
+    /// <returns>The cosine of <paramref name="x"/>.</returns>
+    public static float Cos(float x) => MathF.Cos(x);
+
+    /// <summary>
+    /// Returns the sine of a number.
+    /// </summary>
+    /// <param name="x">The number.</param>
+    /// <returns>The sine of <paramref name="x"/>.</returns>
+    public static float Sin(float x) => MathF.Sin(x);
+
     /// <summary>
     /// Returns the arccosine of a number.
     /// </summary>
@@ -74,7 +89,7 @@ public static class Math
     /// <param name="min">The minimum value.</param>
     /// <param name="max">The maximum value.</param>
     /// <returns>The clamped value.</returns>
-    public static T Clamp<T>(this T x, T min, T max) where T : INumber<T> => (x < min) ? min : (x > max) ? max : x;
+    public static T Clamp<T>(T x, T min, T max) where T : INumber<T> => (x < min) ? min : (x > max) ? max : x;
 
     /// <summary>
     /// Returns the smallest integral value that is greater than or equal to the specified number.
@@ -156,6 +171,16 @@ public static class Math
     /// <returns>The number <paramref name="x"/> raised to the power <paramref name="y"/>.</returns>
     public static float Pow(float x, float y) => MathF.Pow(x, y);
 
+    /// <summary>
+    /// Performs linear interpolation between two specified values.
+    /// </summary>
+    /// <typeparam name="T">The type of the values, which must implement <see cref="IFloatingPoint{T}"/>.</typeparam>
+    /// <param name="x">The starting value of the interpolation.</param>
+    /// <param name="y">The ending value of the interpolation.</param>
+    /// <param name="t">The interpolation factor, typically in the range [0, 1].</param>
+    /// <returns>A value that represents the linear interpolation between <paramref name="x"/> and <paramref name="y"/>.</returns>
+    public static T Lerp<T>(T x, T y, T t) where T : IFloatingPoint<T> => x + (y - x) * t;
+
     /// <summary>
     /// Rounds a number to a specified number of fractional digits.
     /// </summary>
@@ -186,5 +211,4 @@ public static class Math
     /// <param name="x">The number.</param>
     /// <returns>The integral part of <paramref name="x"/>.</returns>
     public static float Truncate(float x) => MathF.Truncate(x);
-
 }

Engine.Core/MathExtensions.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Numerics;
+
+namespace Syntriax.Engine.Core;
+
+public static class MathExtensions
+{
+    /// <inheritdoc cref="Math.Abs{T}(T)" />
+    public static T Abs<T>(this T x) where T : INumber<T> => Math.Abs(x);
+
+    /// <inheritdoc cref="Math.Cos(float)" />
+    public static float Cos(this float x) => Math.Cos(x);
+
+    /// <inheritdoc cref="Math.Sin(float)" />
+    public static float Sin(this float x) => Math.Sin(x);
+
+    /// <inheritdoc cref="Math.Acos(float)" />
+    public static float Acos(this float x) => Math.Acos(x);
+
+    /// <inheritdoc cref="Math.Asin(float)" />
+    public static float Asin(this float x) => Math.Asin(x);
+
+    /// <inheritdoc cref="Math.Atan2(float, float)" />
+    public static float Atan2(this float y, float x) => Math.Atan2(y, x);
+
+    /// <inheritdoc cref="Math.Atanh(float)" />
+    public static float Atanh(this float x) => Math.Atanh(x);
+
+    /// <inheritdoc cref="Math.Clamp{T}(T, T, T)" />
+    public static T Clamp<T>(this T x, T min, T max) where T : INumber<T> => Math.Clamp(x, min, max);
+
+    /// <inheritdoc cref="Math.Ceiling(float)" />
+    public static float Ceiling(this float x) => Math.Ceiling(x);
+
+    /// <inheritdoc cref="Math.CopySign(float, float)" />
+    public static float CopySign(this float x, float y) => Math.CopySign(x, y);
+
+    /// <inheritdoc cref="Math.Floor(float)" />
+    public static float Floor(this float x) => Math.Floor(x);
+
+    /// <inheritdoc cref="Math.IEEERemainder(float, float)" />
+    public static float IEEERemainder(this float x, float y) => Math.IEEERemainder(x, y);
+
+    /// <inheritdoc cref="Math.Log(float, float)" />
+    public static float Log(this float x, float y) => Math.Log(x, y);
+
+    /// <inheritdoc cref="Math.Max{T}(T, T)" />
+    public static T Max<T>(this T x, T y) where T : INumber<T> => Math.Max(x, y);
+
+    /// <inheritdoc cref="Math.AbsMax{T}(T, T)" />
+    public static T AbsMax<T>(this T x, T y) where T : INumber<T> => Math.AbsMax(x, y);
+
+    /// <inheritdoc cref="Math.Min{T}(T, T)" />
+    public static T Min<T>(this T x, T y) where T : INumber<T> => Math.Min(x, y);
+
+    /// <inheritdoc cref="Math.AbsMin{T}(T, T)" />
+    public static T AbsMin<T>(this T x, T y) where T : INumber<T> => Math.AbsMin(x, y);
+
+    /// <inheritdoc cref="Math.Pow(float, float)" />
+    public static float Pow(this float x, float y) => Math.Pow(x, y);
+
+    /// <inheritdoc cref="Math.Lerp{T}(T, T, T)" />
+    public static T Lerp<T>(this T x, T y, T t) where T : IFloatingPoint<T> => Math.Lerp(x, y, t);
+
+    /// <inheritdoc cref="Math.Round(float, int, MidpointRounding)" />
+    public static float Round(this float x, int digits, MidpointRounding mode) => Math.Round(x, digits, mode);
+
+    /// <inheritdoc cref="Math.Sqr{T}(T)" />
+    public static T Sqr<T>(this T x) where T : INumber<T> => Math.Sqr(x);
+
+    /// <inheritdoc cref="Math.Sqrt(float)" />
+    public static float Sqrt(this float x) => Math.Sqrt(x);
+
+    /// <inheritdoc cref="Math.Truncate(float)" />
+    public static float Truncate(this float x) => Math.Truncate(x);
+}

Engine.Core/StateEnable.cs

@@ -1,14 +1,12 @@
-using System;
-
 using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
 
 public class StateEnable : IStateEnable
 {
-    public Action<IAssignable>? OnUnassigned { get; set; } = null;
+    public event IAssignable.OnUnassignedDelegate? OnUnassigned = null;
-    public Action<IAssignableEntity>? OnEntityAssigned { get; set; } = null;
+    public event IAssignableEntity.OnEntityAssignedDelegate? OnEntityAssigned = null;
-    public Action<IStateEnable>? OnEnabledChanged { get; set; } = null;
+    public event IStateEnable.OnNameChangedDelegate? OnEnabledChanged = null;
 
     private bool _enabled = true;
     private IEntity _entity = null!;
@@ -23,14 +21,15 @@ public class StateEnable : IStateEnable
             if (value == _enabled)
                 return;
 
+            bool previousState = _enabled;
             _enabled = value;
-            OnEnabledChanged?.Invoke(this);
+            OnEnabledChanged?.Invoke(this, previousState);
         }
     }
 
     public bool Assign(IEntity entity)
     {
-        if (_entity is not null && _entity.Initialized)
+        if (_entity is not null && _entity.IsInitialized)
             return false;
 
         _entity = entity;

Engine.Core/Transform.cs

@@ -1,20 +1,41 @@
-using System;
+using System.Collections;
+using System.Collections.Generic;
 
 using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Core;
 
-[System.Diagnostics.DebuggerDisplay("Position: {Position.ToString(), nq}, Scale: {Scale.ToString(), nq}, Rotation: {Rotation}")]
+[System.Diagnostics.DebuggerDisplay("Name: {GameObject.Name, nq} Position: {Position.ToString(), nq}, Scale: {Scale.ToString(), nq}, Rotation: {Rotation}")]
 public class Transform : ITransform
 {
-    public Action<ITransform>? OnPositionChanged { get; set; } = null;
+    public event IAssignableGameObject.OnGameObjectAssignedDelegate? OnGameObjectAssigned = null;
-    public Action<ITransform>? OnScaleChanged { get; set; } = null;
+
-    public Action<ITransform>? OnRotationChanged { get; set; } = null;
+    public event IAssignable.OnUnassignedDelegate? OnUnassigned = null;
+
+    public event ITransform.OnPositionChangedDelegate? OnPositionChanged = null;
+    public event ITransform.OnScaleChangedDelegate? OnScaleChanged = null;
+    public event ITransform.OnRotationChangedDelegate? OnRotationChanged = null;
+
+    public event ITransform.OnParentChangedDelegate? OnParentChanged = null;
+    public event ITransform.OnChildrenAddedDelegate? OnChildrenAdded = null;
+    public event ITransform.OnChildrenRemovedDelegate? OnChildrenRemoved = null;
+
 
     private Vector2D _position = Vector2D.Zero;
     private Vector2D _scale = Vector2D.One;
     private float _rotation = 0f;
 
+    private Vector2D _localPosition = Vector2D.Zero;
+    private Vector2D _localScale = Vector2D.One;
+    private float _localRotation = 0f;
+
+    private readonly List<ITransform> _children = [];
+
+    public IGameObject GameObject { get; private set; } = null!;
+    public ITransform? Parent { get; private set; } = null;
+
+    public IReadOnlyList<ITransform> Children => _children;
+
     public Vector2D Position
     {
         get => _position;
@@ -24,33 +45,238 @@ public class Transform : ITransform
                 return;
 
             _position = value;
+            UpdateLocalPosition();
             OnPositionChanged?.Invoke(this);
         }
     }
 
     public Vector2D Scale
     {
-        get => _scale;
+        get => _localScale.Scale(Parent?.Scale ?? Vector2D.One);
         set
         {
             if (value == _scale)
                 return;
 
             _scale = value;
+            UpdateLocalScale();
             OnScaleChanged?.Invoke(this);
         }
     }
 
     public float Rotation
     {
-        get => _rotation;
+        get => _localRotation + (Parent?.Rotation ?? 0f);
         set
         {
             if (value == _rotation)
                 return;
 
             _rotation = value;
+            UpdateLocalPosition();
             OnRotationChanged?.Invoke(this);
         }
     }
+
+    public Vector2D LocalPosition
+    {
+        get => _localPosition;
+        set
+        {
+            if (value == _localPosition)
+                return;
+
+            _localPosition = value;
+            UpdatePosition();
+            OnPositionChanged?.Invoke(this);
+        }
+    }
+
+    public Vector2D LocalScale
+    {
+        get => _localScale;
+        set
+        {
+            if (value == _localScale)
+                return;
+
+            _localScale = value;
+            UpdateScale();
+            OnScaleChanged?.Invoke(this);
+        }
+    }
+
+    public float LocalRotation
+    {
+        get => _localRotation;
+        set
+        {
+            if (value == _localRotation)
+                return;
+
+            _localRotation = value;
+            UpdateRotation();
+            OnRotationChanged?.Invoke(this);
+        }
+    }
+
+    public void SetParent(ITransform? transform)
+    {
+        if (transform == this || Parent == transform)
+            return;
+
+        ITransform? previousParent = Parent;
+        if (previousParent is not null)
+        {
+            previousParent.RemoveChild(this);
+            previousParent.OnPositionChanged -= RecalculatePosition;
+            previousParent.OnScaleChanged -= RecalculateScale;
+            previousParent.OnRotationChanged -= RecalculateRotation;
+            previousParent.OnParentChanged -= NotifyChildrenOnParentChange;
+        }
+
+        Parent = transform;
+
+        if (transform is not null)
+        {
+            transform.AddChild(this);
+            transform.OnPositionChanged += RecalculatePosition;
+            transform.OnScaleChanged += RecalculateScale;
+            transform.OnRotationChanged += RecalculateRotation;
+            transform.OnParentChanged += NotifyChildrenOnParentChange;
+        }
+
+        UpdateLocalPosition();
+        UpdateLocalScale();
+        UpdateLocalRotation();
+
+        OnParentChanged?.Invoke(this, previousParent, transform);
+    }
+
+    public void AddChild(ITransform transform)
+    {
+        if (_children.Contains(transform))
+            return;
+
+        _children.Add(transform);
+        transform.SetParent(this);
+        OnChildrenAdded?.Invoke(this, transform);
+    }
+
+    public void RemoveChild(ITransform transform)
+    {
+        if (!_children.Remove(transform))
+            return;
+
+        transform.SetParent(null);
+        OnChildrenRemoved?.Invoke(this, transform);
+    }
+
+    public IEnumerator<ITransform> GetEnumerator() => _children.GetEnumerator();
+    IEnumerator IEnumerable.GetEnumerator() => _children.GetEnumerator();
+
+    private void NotifyChildrenOnParentChange(ITransform transform, ITransform? previousParent, ITransform? newParent)
+    {
+        // TODO No idea how logical this is to propagate this to the children the way I'm doing right now.
+        // I was originally gonna just call `child.OnParentChanged?.Invoke(child, child.Parent);` but seems an unnecessary call too?
+        foreach (var child in Children) // TODO CHECK ERRORS
+            child.SetParent(this);
+    }
+
+    private void RecalculatePosition(ITransform _)
+    {
+        if (Parent is null)
+            return;
+
+        UpdatePosition();
+        OnPositionChanged?.Invoke(this);
+    }
+
+    private void RecalculateScale(ITransform _)
+    {
+        if (Parent is null)
+            return;
+
+        UpdateScale();
+        OnScaleChanged?.Invoke(this);
+    }
+
+    private void RecalculateRotation(ITransform _)
+    {
+        if (Parent is null)
+            return;
+
+        UpdatePosition();
+        UpdateRotation();
+        OnPositionChanged?.Invoke(this);
+        OnRotationChanged?.Invoke(this);
+    }
+
+    private void UpdateLocalPosition()
+    {
+        if (Parent is null)
+            _localPosition = Position;
+        else
+            _localPosition = Parent.Position.FromTo(Position).Scale(Parent.Scale);
+    }
+
+    private void UpdateLocalScale()
+    {
+        if (Parent is null)
+            _localScale = Scale;
+        else
+            _localScale = Scale.Scale(new(1f / Parent.Scale.X, 1f / Parent.Scale.Y));
+    }
+
+    private void UpdateLocalRotation()
+    {
+        if (Parent is null)
+            _localRotation = Rotation;
+        else
+            _localRotation = Rotation - Parent.Rotation;
+    }
+
+    private void UpdatePosition()
+    {
+        if (Parent is null)
+            _position = LocalPosition.Rotate(0f * Math.DegreeToRadian);
+        else
+            _position = Parent.Position + LocalPosition.Scale(new(Parent.Scale.X, Parent.Scale.Y)).Rotate(Parent.Rotation * Math.DegreeToRadian);
+    }
+
+    private void UpdateScale()
+    {
+        if (Parent is null)
+            _scale = LocalScale;
+        else
+            _scale = Vector2D.Scale(Parent.Scale, LocalScale);
+    }
+
+    private void UpdateRotation()
+    {
+        if (Parent is null)
+            _rotation = LocalRotation;
+        else
+            _rotation = Parent.Rotation + LocalRotation;
+    }
+
+    public bool Assign(IGameObject gameObject)
+    {
+        if (GameObject is not null && GameObject.IsInitialized)
+            return false;
+
+        GameObject = gameObject;
+        OnGameObjectAssigned?.Invoke(this);
+        return true;
+    }
+
+    public bool Unassign()
+    {
+        if (GameObject is not null && GameObject.IsInitialized)
+            return false;
+
+        GameObject = null!;
+        OnUnassigned?.Invoke(this);
+        return true;
+    }
 }

Engine.Input/Abstract/IButtonInputs.cs

@@ -4,11 +4,12 @@ namespace Syntriax.Engine.Input;
 
 public interface IButtonInputs<T> : IAssignableStateEnable
 {
-    void RegisterOnPress(T button, Action<IButtonInputs<T>, T> callback);
+    void RegisterOnPress(T button, ButtonCallbackDelegate callback);
-    void UnregisterOnPress(T button, Action<IButtonInputs<T>, T> callback);
+    void UnregisterOnPress(T button, ButtonCallbackDelegate callback);
-    void RegisterOnRelease(T button, Action<IButtonInputs<T>, T> callback);
+    void RegisterOnRelease(T button, ButtonCallbackDelegate callback);
-    void UnregisterOnRelease(T button, Action<IButtonInputs<T>, T> callback);
+    void UnregisterOnRelease(T button, ButtonCallbackDelegate callback);
 
     bool IsPressed(T button);
-    bool WasPressed(T button);
+
+    delegate void ButtonCallbackDelegate(IButtonInputs<T> buttonInputs, T button);
 }

Engine.Physics2D/Abstract/ICollider2D.cs

@@ -1,5 +1,3 @@
-using System;
-
 using Syntriax.Engine.Core.Abstract;
 
 namespace Syntriax.Engine.Physics2D.Abstract;
@@ -12,17 +10,17 @@ public interface ICollider2D : IBehaviour, IAssignableTransform
     /// <summary>
     /// Event triggered when a collision is detected.
     /// </summary>
-    Action<ICollider2D, CollisionDetectionInformation>? OnCollisionDetected { get; set; }
+    event OnCollisionDetectedDelegate? OnCollisionDetected;
 
     /// <summary>
     /// Event triggered when a collision is resolved.
     /// </summary>
-    Action<ICollider2D, CollisionDetectionInformation>? OnCollisionResolved { get; set; }
+    event OnCollisionResolvedDelegate? OnCollisionResolved;
 
     /// <summary>
     /// Event triggered when another <see cref="ICollider2D"/> triggers this <see cref="ICollider2D"/>.
     /// </summary>
-    Action<ICollider2D, ICollider2D>? OnTriggered { get; set; }
+    event OnTriggeredDelegate? OnTriggered;
 
     /// <summary>
     /// The <see cref="IRigidBody2D"/> associated with the <see cref="ICollider2D"/>.
@@ -38,4 +36,12 @@ public interface ICollider2D : IBehaviour, IAssignableTransform
     /// Recalculates <see cref="ICollider2D"/> properties.
     /// </summary>
     void Recalculate();
+
+    void Detect(CollisionDetectionInformation collisionDetectionInformation);
+    void Resolve(CollisionDetectionInformation collisionDetectionInformation);
+    void Trigger(ICollider2D initiator);
+
+    delegate void OnCollisionDetectedDelegate(ICollider2D sender, CollisionDetectionInformation collisionDetectionInformation);
+    delegate void OnCollisionResolvedDelegate(ICollider2D sender, CollisionDetectionInformation collisionDetectionInformation);
+    delegate void OnTriggeredDelegate(ICollider2D sender, ICollider2D initiatorCollider);
 }

Engine.Physics2D/Abstract/IPhysicsEngine2D.cs

@@ -5,6 +5,16 @@ namespace Syntriax.Engine.Physics2D.Abstract;
 /// </summary>
 public interface IPhysicsEngine2D
 {
+    /// <summary>
+    /// Event triggered when the <see cref="IPhysicsEngine2D"/> has done a single physics iteration.
+    /// </summary>
+    event OnPhysicsIterationDelegate? OnPhysicsIteration;
+
+    /// <summary>
+    /// Event triggered when the <see cref="IPhysicsEngine2D"/> has done a full physics step/>.
+    /// </summary>
+    event OnPhysicsStepDelegate? OnPhysicsStep;
+
     /// <summary>
     /// The number of iterations the <see cref="IPhysicsEngine2D"/> performs per step.
     /// </summary>
@@ -15,4 +25,7 @@ public interface IPhysicsEngine2D
     /// </summary>
     /// <param name="deltaTime">The time step.</param>
     void Step(float deltaTime);
+
+    delegate void OnPhysicsIterationDelegate(IPhysicsEngine2D sender, float iterationDeltaTime);
+    delegate void OnPhysicsStepDelegate(IPhysicsEngine2D sender, float stepDeltaTime);
 }

Engine.Physics2D/Abstract/IPhysicsUpdate.cs

@@ -0,0 +1,15 @@
+using Syntriax.Engine.Core.Abstract;
+
+namespace Syntriax.Engine.Physics2D.Abstract;
+
+/// <summary>
+/// Represents a <see cref="IBehaviour"/> that listens to physics simulation update phase.
+/// </summary>
+public interface IPhysicsUpdate : IBehaviour
+{
+    /// <summary>
+    /// Updates the physics state of the object based on the elapsed time since the last update.
+    /// </summary>
+    /// <param name="delta">The time elapsed since the last physics update, typically in seconds.</param>
+    void PhysicsUpdate(float delta);
+}

Engine.Physics2D/Collider2DBehaviourBase.cs

@@ -1,16 +1,14 @@
-using System;
-
 using Syntriax.Engine.Core;
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Physics2D.Abstract;
 
 namespace Syntriax.Engine.Physics2D;
 
-public abstract class Collider2DBehaviourBase : BehaviourOverride, ICollider2D
+public abstract class Collider2DBehaviourBase : Behaviour, ICollider2D
 {
-    public Action<ICollider2D, CollisionDetectionInformation>? OnCollisionDetected { get; set; } = null;
+    public event ICollider2D.OnCollisionDetectedDelegate? OnCollisionDetected = null;
-    public Action<ICollider2D, CollisionDetectionInformation>? OnCollisionResolved { get; set; } = null;
+    public event ICollider2D.OnCollisionResolvedDelegate? OnCollisionResolved = null;
-    public Action<ICollider2D, ICollider2D>? OnTriggered { get; set; } = null;
+    public event ICollider2D.OnTriggeredDelegate? OnTriggered = null;
 
 
     protected bool NeedsRecalculation { get; private set; } = true;
@@ -20,7 +18,7 @@ public abstract class Collider2DBehaviourBase : BehaviourOverride, ICollider2D
     public bool IsTrigger { get; set; } = false;
 
     ITransform IAssignableTransform.Transform => Transform;
-    Action<IAssignableTransform>? IAssignableTransform.OnTransformAssigned { get => GameObject.OnTransformAssigned; set => GameObject.OnTransformAssigned = value; }
+    public event IAssignableTransform.OnTransformAssignedDelegate? OnTransformAssigned { add => GameObject.OnTransformAssigned += value; remove => GameObject.OnTransformAssigned -= value; }
 
     bool IAssignableTransform.Assign(ITransform transform) => GameObject.Assign(transform);
 
@@ -37,7 +35,7 @@ public abstract class Collider2DBehaviourBase : BehaviourOverride, ICollider2D
 
     protected override void OnInitialize()
     {
-        BehaviourController.TryGetBehaviour(out _rigidBody2D);
+        BehaviourController.TryGetBehaviourInParent(out _rigidBody2D);
 
         BehaviourController.OnBehaviourAdded += OnBehaviourAddedToController;
         BehaviourController.OnBehaviourRemoved += OnBehaviourRemovedFromController;
@@ -45,6 +43,12 @@ public abstract class Collider2DBehaviourBase : BehaviourOverride, ICollider2D
         Transform.OnPositionChanged += SetNeedsRecalculation;
         Transform.OnRotationChanged += SetNeedsRecalculation;
         Transform.OnScaleChanged += SetNeedsRecalculation;
+        Transform.OnParentChanged += UpdateRigidBody2D;
+    }
+
+    private void UpdateRigidBody2D(ITransform sender, ITransform? previousParent, ITransform? newParent)
+    {
+        BehaviourController.TryGetBehaviourInParent(out _rigidBody2D);
     }
 
     private void OnBehaviourAddedToController(IBehaviourController _, IBehaviour behaviour)
@@ -70,4 +74,8 @@ public abstract class Collider2DBehaviourBase : BehaviourOverride, ICollider2D
         Transform.OnPositionChanged -= SetNeedsRecalculation;
         Transform.OnRotationChanged -= SetNeedsRecalculation;
     }
+
+    public void Detect(CollisionDetectionInformation collisionDetectionInformation) => OnCollisionDetected?.Invoke(this, collisionDetectionInformation);
+    public void Resolve(CollisionDetectionInformation collisionDetectionInformation) => OnCollisionResolved?.Invoke(this, collisionDetectionInformation);
+    public void Trigger(ICollider2D initiator) => OnTriggered?.Invoke(this, initiator);
 }

Engine.Physics2D/CollisionDetectionInformation.cs

@@ -6,14 +6,16 @@ namespace Syntriax.Engine.Physics2D;
 [System.Diagnostics.DebuggerDisplay("Normal: {Normal.ToString(), nq}, Penetration: {Penetration}")]
 public readonly struct CollisionDetectionInformation
 (
-    ICollider2D Left,
+    ICollider2D Detector,
-    ICollider2D Right,
+    ICollider2D Detected,
     Vector2D Normal,
     float Penetration
 )
 {
-    public ICollider2D Left { get; init; } = Left;
+    public ICollider2D Detector { get; init; } = Detector;
-    public ICollider2D Right { get; init; } = Right;
+    public ICollider2D Detected { get; init; } = Detected;
     public Vector2D Normal { get; init; } = Normal;
     public float Penetration { get; init; } = Penetration;
+
+    public CollisionDetectionInformation Reverse() => new(Detected, Detector, -Normal, Penetration);
 }

Engine.Physics2D/CollisionDetector2D.cs

@@ -55,7 +55,7 @@ public class CollisionDetector2D : ICollisionDetector2D
             if (!leftProjection.Overlaps(rightProjection, out float depth))
                 return false;
 
-            if (collisionInformation.Left is null || Math.Abs(collisionInformation.Penetration) > Math.Abs(depth))
+            if (collisionInformation.Detector is null || Math.Abs(collisionInformation.Penetration) > Math.Abs(depth))
                 collisionInformation = new(left, right, projectionVector, depth);
         }
 
@@ -79,7 +79,7 @@ public class CollisionDetector2D : ICollisionDetector2D
             if (!shapeProjection.Overlaps(circleProjection, out float depth))
                 return false;
 
-            if (collisionInformation.Left is null || Math.Abs(collisionInformation.Penetration) > Math.Abs(depth))
+            if (collisionInformation.Detector is null || Math.Abs(collisionInformation.Penetration) > Math.Abs(depth))
                 collisionInformation = new(shapeCollider, circleCollider, projectionVector, depth);
         }
 
@@ -92,7 +92,7 @@ public class CollisionDetector2D : ICollisionDetector2D
             if (!shapeProjection.Overlaps(circleProjection, out float depth))
                 return false;
 
-            if (collisionInformation.Left is null || Math.Abs(collisionInformation.Penetration) > Math.Abs(depth))
+            if (collisionInformation.Detector is null || Math.Abs(collisionInformation.Penetration) > Math.Abs(depth))
                 collisionInformation = new(shapeCollider, circleCollider, shapeToCircleProjectionVector, depth);
         }
 

Engine.Physics2D/CollisionResolver2D.cs

@@ -9,8 +9,8 @@ public class CollisionResolver2D : ICollisionResolver2D
     {
         Vector2D displacementVector = collisionInformation.Normal * collisionInformation.Penetration;
 
-        ICollider2D left = collisionInformation.Left;
+        ICollider2D left = collisionInformation.Detector;
-        ICollider2D right = collisionInformation.Right;
+        ICollider2D right = collisionInformation.Detected;
 
         bool isLeftStatic = left.RigidBody2D?.IsStatic ?? true;
         bool isRightStatic = right.RigidBody2D?.IsStatic ?? true;
@@ -38,7 +38,7 @@ public class CollisionResolver2D : ICollisionResolver2D
         left.Recalculate();
         right.Recalculate();
 
-        left.OnCollisionResolved?.Invoke(collisionInformation.Left, collisionInformation);
+        left.Resolve(collisionInformation);
-        right.OnCollisionResolved?.Invoke(right, collisionInformation);
+        right.Resolve(collisionInformation);
     }
 }

Engine.Physics2D/Physics2D.cs

@@ -1,13 +1,33 @@
-using System;
-
 using Syntriax.Engine.Core;
-using Syntriax.Engine.Physics2D;
 using Syntriax.Engine.Physics2D.Primitives;
 
 namespace Engine.Physics2D;
 
 public static partial class Physics2D
 {
+    public static bool Overlaps(this Shape shape, Vector2D point) => Overlaps(shape, point, out var _);
+    public static bool Overlaps(this Shape shape, Vector2D point, out float depth)
+    {
+        depth = float.MaxValue;
+        var vertices = shape.Vertices;
+        int count = vertices.Count;
+
+        for (int indexProjection = 0; indexProjection < count; indexProjection++)
+        {
+            Vector2D projectionVector = vertices[indexProjection].FromTo(vertices[(indexProjection + 1) % count]).Perpendicular().Normalized;
+
+            Projection shapeProjection = shape.ToProjection(projectionVector);
+            float projectedPoint = point.Dot(projectionVector);
+
+            if (shapeProjection.Max < projectedPoint || shapeProjection.Min > projectedPoint)
+                return false;
+
+            depth = Math.Min(depth, Math.Abs(Math.AbsMin(shapeProjection.Max - projectedPoint, shapeProjection.Min - projectedPoint)));
+        }
+
+        return true;
+    }
+
     public static bool Overlaps(this Circle left, Circle right)
     {
         float distanceSquared = left.Center.FromTo(right.Center).LengthSquared();
@@ -27,7 +47,7 @@ public static partial class Physics2D
         normal = distanceVector.Normalized;
 
         if (isOverlapping)
-            depth = MathF.Sqrt(radiusSumSquared - distanceSquared);
+            depth = Math.Sqrt(radiusSumSquared - distanceSquared);
 
         return isOverlapping;
     }
@@ -44,7 +64,7 @@ public static partial class Physics2D
         normal = distanceVector.Normalized;
 
         if (isOverlapping)
-            depth = MathF.Sqrt(radiusSquared - distanceSquared);
+            depth = Math.Sqrt(radiusSquared - distanceSquared);
 
         return isOverlapping;
     }

Engine.Physics2D/PhysicsCoroutineManager.cs

@@ -0,0 +1,67 @@
+using System.Collections;
+using System.Collections.Generic;
+
+using Syntriax.Engine.Core;
+using Syntriax.Engine.Core.Abstract;
+using Syntriax.Engine.Physics2D.Abstract;
+
+namespace Engine.Physics2D;
+
+public class PhysicsCoroutineManager : HierarchyObjectBase
+{
+    private readonly List<IEnumerator> enumerators = [];
+    private IPhysicsEngine2D? physicsEngine = null;
+
+
+    public IEnumerator CreateCoroutine(IEnumerator enumerator)
+    {
+        enumerators.Add(enumerator);
+        return enumerator;
+    }
+
+    public void StopCoroutine(IEnumerator enumerator)
+    {
+        enumerators.Remove(enumerator);
+    }
+
+    protected override void OnEnteringHierarchy(IGameManager gameManager)
+    {
+        physicsEngine = gameManager.HierarchyObjects.FindObject<IPhysicsEngine2D>();
+        if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
+            foundPhysicsEngine.OnPhysicsStep += OnPhysicsStep;
+        else
+            gameManager.OnUpdate += OnUpdate;
+    }
+
+    private void OnPhysicsStep(IPhysicsEngine2D sender, float stepDeltaTime)
+    {
+        for (int i = enumerators.Count - 1; i >= 0; i--)
+        {
+            if (enumerators[i].Current is ICoroutineYield coroutineYield && coroutineYield.Yield())
+                continue;
+
+            if (!enumerators[i].MoveNext())
+                enumerators.RemoveAt(i);
+        }
+    }
+
+    protected override void OnExitingHierarchy(IGameManager gameManager)
+    {
+        if (physicsEngine is IPhysicsEngine2D existingPhysicsEngine)
+            existingPhysicsEngine.OnPhysicsStep -= OnPhysicsStep;
+        gameManager.OnUpdate -= OnUpdate;
+    }
+
+    private void OnUpdate(IGameManager sender, EngineTime time)
+    {
+        if (GameManager is not IGameManager gameManager)
+            return;
+
+        physicsEngine = gameManager.HierarchyObjects.FindObject<IPhysicsEngine2D>();
+        if (physicsEngine is IPhysicsEngine2D foundPhysicsEngine)
+        {
+            foundPhysicsEngine.OnPhysicsStep += OnPhysicsStep;
+            gameManager.OnUpdate -= OnUpdate;
+        }
+    }
+}

Engine.Physics2D/PhysicsEngine2D.cs

@@ -1,6 +1,5 @@
 using System.Collections.Generic;
 
-using Syntriax.Engine.Core;
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Physics2D.Abstract;
 
@@ -8,6 +7,9 @@ namespace Syntriax.Engine.Physics2D;
 
 public class PhysicsEngine2D : IPhysicsEngine2D
 {
+    public event IPhysicsEngine2D.OnPhysicsIterationDelegate? OnPhysicsIteration = null;
+    public event IPhysicsEngine2D.OnPhysicsStepDelegate? OnPhysicsStep = null;
+
     private readonly List<IRigidBody2D> rigidBodies = new(32);
     private readonly List<ICollider2D> colliders = new(64);
 
@@ -72,7 +74,7 @@ public class PhysicsEngine2D : IPhysicsEngine2D
                     if (bothCollidersAreTriggers)
                         continue;
 
-                    bool bothCollidersAreStatic = colliderX.RigidBody2D?.IsStatic ?? true && colliderX.RigidBody2D?.IsStatic == colliderY.RigidBody2D?.IsStatic;
+                    bool bothCollidersAreStatic = (colliderX.RigidBody2D?.IsStatic ?? true) && (colliderY.RigidBody2D?.IsStatic ?? true);
                     if (bothCollidersAreStatic)
                         continue;
 
@@ -80,23 +82,33 @@ public class PhysicsEngine2D : IPhysicsEngine2D
                     {
                         if (colliderX.IsTrigger)
                         {
-                            colliderX.OnTriggered?.Invoke(colliderX, colliderY);
+                            colliderX.Trigger(colliderY);
                             continue;
                         }
                         else if (colliderY.IsTrigger)
                         {
-                            colliderY.OnTriggered?.Invoke(colliderY, colliderY);
+                            colliderY.Trigger(colliderY);
                             continue;
                         }
 
-                        colliderX.OnCollisionDetected?.Invoke(colliderX, information);
+                        if (information.Detector == colliderX)
-                        colliderY.OnCollisionDetected?.Invoke(colliderY, information);
+                        {
+                            colliderX.Detect(information);
+                            colliderY.Detect(information.Reverse());
+                        }
+                        else
+                        {
+                            colliderX.Detect(information.Reverse());
+                            colliderY.Detect(information);
+                        }
 
                         collisionResolver?.Resolve(information);
                     }
                 }
             }
+            OnPhysicsIteration?.Invoke(this, intervalDeltaTime);
         }
+        OnPhysicsStep?.Invoke(this, deltaTime);
     }
 
     private static void StepRigidBody(IRigidBody2D rigidBody, float intervalDeltaTime)

Engine.Physics2D/PhysicsEngine2DCollector.cs

@@ -1,28 +1,25 @@
-using System;
-
 using Syntriax.Engine.Core;
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Physics2D.Abstract;
 
 namespace Syntriax.Engine.Physics2D;
 
-public class PhysicsEngine2DCacher : IPhysicsEngine2D, IAssignableGameManager
+public class PhysicsEngine2DCollector : HierarchyObjectBase, IPhysicsEngine2D
 {
-    public Action<IAssignable>? OnUnassigned { get; set; } = null;
+    public event IPhysicsEngine2D.OnPhysicsIterationDelegate? OnPhysicsIteration = null;
-    public Action<IAssignableGameManager>? OnGameManagerAssigned { get; set; } = null;
+    public event IPhysicsEngine2D.OnPhysicsStepDelegate? OnPhysicsStep = null;
-
 
     private int _iterationPerStep = 1;
 
     protected readonly ICollisionDetector2D collisionDetector = null!;
     protected readonly ICollisionResolver2D collisionResolver = null!;
 
-    protected BehaviourCacher<IRigidBody2D> rigidBodyCacher = new();
+    protected BehaviourCollector<IRigidBody2D> rigidBodyCollector = new();
-    protected BehaviourCacher<ICollider2D> colliderCacher = new();
+    protected BehaviourCollector<ICollider2D> colliderCollector = new();
+    protected BehaviourCollector<IPhysicsUpdate> physicsUpdateCollector = new();
 
 
     public int IterationPerStep { get => _iterationPerStep; set => _iterationPerStep = value < 1 ? 1 : value; }
-    public IGameManager GameManager { get; private set; } = null!;
 
     public void Step(float deltaTime)
     {
@@ -31,23 +28,23 @@ public class PhysicsEngine2DCacher : IPhysicsEngine2D, IAssignableGameManager
         for (int iterationIndex = 0; iterationIndex < IterationPerStep; iterationIndex++)
         {
             // Can Parallel
-            foreach (var rigidBody in rigidBodyCacher)
+            foreach (var rigidBody in rigidBodyCollector)
                 StepRigidBody(rigidBody, intervalDeltaTime);
 
             // Can Parallel
-            foreach (var collider in colliderCacher)
+            foreach (var collider in colliderCollector)
                 collider.Recalculate();
 
             // Can Parallel
-            for (int x = 0; x < colliderCacher.Behaviours.Count; x++)
+            for (int x = 0; x < colliderCollector.Behaviours.Count; x++)
             {
-                ICollider2D? colliderX = colliderCacher.Behaviours[x];
+                ICollider2D? colliderX = colliderCollector.Behaviours[x];
                 if (!colliderX.IsActive)
                     return;
 
-                for (int y = x + 1; y < colliderCacher.Behaviours.Count; y++)
+                for (int y = x + 1; y < colliderCollector.Behaviours.Count; y++)
                 {
-                    ICollider2D? colliderY = colliderCacher.Behaviours[y];
+                    ICollider2D? colliderY = colliderCollector.Behaviours[y];
 
                     if (!colliderY.IsActive)
                         return;
@@ -59,7 +56,7 @@ public class PhysicsEngine2DCacher : IPhysicsEngine2D, IAssignableGameManager
                     if (bothCollidersAreTriggers)
                         continue;
 
-                    bool bothCollidersAreStatic = colliderX.RigidBody2D?.IsStatic ?? true && colliderX.RigidBody2D?.IsStatic == colliderY.RigidBody2D?.IsStatic;
+                    bool bothCollidersAreStatic = (colliderX.RigidBody2D?.IsStatic ?? true) && (colliderY.RigidBody2D?.IsStatic ?? true);
                     if (bothCollidersAreStatic)
                         continue;
 
@@ -67,23 +64,38 @@ public class PhysicsEngine2DCacher : IPhysicsEngine2D, IAssignableGameManager
                     {
                         if (colliderX.IsTrigger)
                         {
-                            colliderX.OnTriggered?.Invoke(colliderX, colliderY);
+                            colliderX.Trigger(colliderY);
                             continue;
                         }
                         else if (colliderY.IsTrigger)
                         {
-                            colliderY.OnTriggered?.Invoke(colliderY, colliderY);
+                            colliderY.Trigger(colliderY);
                             continue;
                         }
 
-                        colliderX.OnCollisionDetected?.Invoke(colliderX, information);
+                        if (information.Detector == colliderX)
-                        colliderY.OnCollisionDetected?.Invoke(colliderY, information);
+                        {
+                            colliderX.Detect(information);
+                            colliderY.Detect(information.Reverse());
+                        }
+                        else
+                        {
+                            colliderX.Detect(information.Reverse());
+                            colliderY.Detect(information);
+                        }
 
                         collisionResolver?.Resolve(information);
                     }
                 }
             }
+
+            OnPhysicsIteration?.Invoke(this, intervalDeltaTime);
         }
+
+        foreach (IPhysicsUpdate physicsUpdate in physicsUpdateCollector)
+            physicsUpdate.PhysicsUpdate(deltaTime);
+
+        OnPhysicsStep?.Invoke(this, deltaTime);
     }
 
     private static void StepRigidBody(IRigidBody2D rigidBody, float intervalDeltaTime)
@@ -94,55 +106,27 @@ public class PhysicsEngine2DCacher : IPhysicsEngine2D, IAssignableGameManager
         rigidBody.Transform.Position += rigidBody.Velocity * intervalDeltaTime;
         rigidBody.Transform.Rotation += rigidBody.AngularVelocity * intervalDeltaTime;
     }
-
+    protected override void OnEnteringHierarchy(IGameManager gameManager)
-    public bool Assign(IGameManager gameManager)
     {
-        if (GameManager is not null)
+        physicsUpdateCollector.Assign(gameManager);
-            return false;
+        colliderCollector.Assign(gameManager);
-
+        rigidBodyCollector.Assign(gameManager);
-        colliderCacher.Assign(gameManager);
-        rigidBodyCacher.Assign(gameManager);
-
-        GameManager = gameManager;
-        OnGameManagerAssigned?.Invoke(this);
-
-        return true;
     }
 
-    public bool Unassign()
+    protected override void OnExitingHierarchy(IGameManager gameManager)
     {
-        if (GameManager is null)
+        physicsUpdateCollector.Unassign();
-            return false;
+        colliderCollector.Unassign();
-
+        rigidBodyCollector.Unassign();
-        colliderCacher.Unassign();
-        rigidBodyCacher.Unassign();
-
-        GameManager = null!;
-        OnUnassigned?.Invoke(this);
-        return true;
     }
 
-    public PhysicsEngine2DCacher()
+    public PhysicsEngine2DCollector()
     {
         collisionDetector = new CollisionDetector2D();
         collisionResolver = new CollisionResolver2D();
     }
 
-    public PhysicsEngine2DCacher(IGameManager gameManager)
+    public PhysicsEngine2DCollector(ICollisionDetector2D collisionDetector, ICollisionResolver2D collisionResolver)
-    {
-        Assign(gameManager);
-        collisionDetector = new CollisionDetector2D();
-        collisionResolver = new CollisionResolver2D();
-    }
-
-    public PhysicsEngine2DCacher(IGameManager gameManager, ICollisionDetector2D collisionDetector, ICollisionResolver2D collisionResolver)
-    {
-        Assign(gameManager);
-        this.collisionDetector = collisionDetector;
-        this.collisionResolver = collisionResolver;
-    }
-
-    public PhysicsEngine2DCacher(ICollisionDetector2D collisionDetector, ICollisionResolver2D collisionResolver)
     {
         this.collisionDetector = collisionDetector;
         this.collisionResolver = collisionResolver;

Engine.Physics2D/Primitives/Circle.cs

@@ -69,7 +69,7 @@ public readonly struct Circle(Vector2D center, float radius)
     /// Transforms the <see cref="Circle"/> by the specified <see cref="ITransform"/>.
     /// </summary>
     public static Circle TransformCircle(ITransform transform, Circle circle)
-        => new(transform.TransformVector2D(circle.Center), circle.Radius * transform.Scale.Magnitude);
+        => new(transform.TransformVector2D(circle.Center), circle.Radius * (transform.Scale.Magnitude / Vector2D.One.Magnitude));
 
     /// <summary>
     /// Checks if two <see cref="Circle"/>s are approximately equal.

Engine.Physics2D/Primitives/Line.cs

@@ -202,6 +202,40 @@ public readonly struct Line(Vector2D from, Vector2D to)
 /// </summary>
 public static class LineExtensions
 {
+    /// <summary>
+    /// Linearly interpolates between the two endpoints of the <see cref="Line"/> segment using parameter 't'.
+    /// </summary>
+    public static Vector2D Lerp(this Line line, float t) => Line.Lerp(line, t);
+
+
+    /// <summary>
+    /// The equation of the <see cref="Line"/> defined by this <see cref="Line"/> segment.
+    /// </summary>
+    public static LineEquation ToLineEquation(this Line line) => Line.GetLineEquation(line);
+
+
+    /// <summary>
+    /// Determines whether the specified <see cref="Vector2D"/> lies on the <see cref="Line"/>.
+    /// </summary>
+    public static bool Intersects(this Line line, Vector2D point) => Line.Intersects(line, point);
+
+    /// <summary>
+    /// Calculates the parameter 't' representing the point's position on the <see cref="Line"/> segment.
+    /// </summary>
+    public static float GetT(this Line line, Vector2D point) => Line.GetT(line, point);
+
+
+    /// <summary>
+    /// Checks if the <see cref="Line"/> segment intersects with another <see cref="Line"/> segment.
+    /// </summary>
+    public static bool Intersects(this Line left, Line right) => Line.Intersects(left, right);
+
+
+    /// <summary>
+    /// Determines whether two <see cref="Line"/> segments intersect.
+    /// </summary>
+    public static bool Intersects(this Line left, Line right, [NotNullWhen(returnValue: true)] out Vector2D? point) => Line.Intersects(left, right, out point);
+
     /// <summary>
     /// Checks if two <see cref="Line"/>s are approximately equal.
     /// </summary>

Engine.Physics2D/RigidBody2D.cs

@@ -1,14 +1,12 @@
-using System;
-
 using Syntriax.Engine.Core;
 using Syntriax.Engine.Core.Abstract;
 using Syntriax.Engine.Physics2D.Abstract;
 
 namespace Syntriax.Engine.Physics2D;
 
-public class RigidBody2D : BehaviourOverride, IRigidBody2D
+public class RigidBody2D : Behaviour, IRigidBody2D
 {
-    public Action<IAssignableTransform>? OnTransformAssigned { get => GameObject.OnTransformAssigned; set => GameObject.OnTransformAssigned = value; }
+    event IAssignableTransform.OnTransformAssignedDelegate? IAssignableTransform.OnTransformAssigned { add => GameObject.OnTransformAssigned += value; remove => GameObject.OnTransformAssigned -= value; }
 
     private const float LOWEST_ALLOWED_MASS = 0.00001f;
     private float _mass = 1f;